Neural Immune mechanisms of heroin withdrawal and stress

项目总结/摘要 阿片类药物戒断和创伤后应激障碍（PTSD）经常出现在临床环境中。 临床数据还表明，阿片类药物滥用是PTSD的潜在危险因素。了解机制 阿片类药物使用者中PTSD的共同发生和脆弱性将提供有关 阿片剂滥用，并为制定减轻海洛因戒断症状的干预措施提供信息， 一个已知的复发风险因素，以及海洛因对应激障碍的长期影响。我们的实验室发现 海马机制发展所需的压力增强恐惧学习（SEFL），一种动物 PTSD模型我们建立了严重的应激在SEFL范式诱导背海马（DH） IL-1受体拮抗剂（IL-1 R）直接阻断DH IL-1信号通路， 1 RA）严重的压力后，防止随后的增强恐惧学习。我们开发了一个临床前模型 探讨海洛因戒断对增强恐惧学习的影响。我们发现， 在SEFL范式中，海洛因给药替代了严重的应激源，海洛因戒断也类似 增加DH IL-1β和GFAP表达，这是星形胶质细胞活化的标志物。因此，计划是测试 创新的独特假设，海洛因戒断也通过海马IL-1β和海马神经元的改变起作用。 导致恐惧学习能力增强的星形胶质细胞。具体目标1将检验海洛因戒断- DH中的IL-1β介导了恐惧学习的诱导增强。具体而言，我们将确定（A）是否 戒断诱导的恐惧学习增强与IL-1β信号的增强有关， 星形胶质细胞，（B）在戒断过程中用IL-1 RA阻断DH IL-1受体是否会保护星形胶质细胞， 海洛因戒断后增强的恐惧学习的发展，（C）是否DH输注外源性IL- 1β将取代压力和/或退缩的影响，以诱导增强的恐惧学习，以及（D）是否 在海洛因戒断期间DHIL-1受体的药理学阻断将防止戒断症状。 预测的结果是，海洛因戒断会增加IL-1β水平，主要是在星形胶质细胞中， 海洛因戒断对增强的恐惧学习的作用将被IL-1 RA阻断，并被IL-1β注入模拟。 的DH。此外，戒断症状将通过施用IL-1 RA而减弱或阻断。 总的来说，这些结果阐明了DH IL-1信号在海洛因戒断和增强恐惧中的关键作用。 学习Specific Aim 2将使用单个细胞的先进三维重建来进行形态测定分析 结合突触标记物（突触后密度95和突触蛋白1）的评估，以测试创新的 假设星形胶质细胞的形态测量特性的变化和/或星形胶质细胞/神经元的改变 相互作用与海洛因戒断和SEFL中使用的严重压力源的影响有关， 并且取决于IL-1信号传导。这些研究测试了关于以下基本机制的独特假设： 海洛因戒断的影响，并为减轻海洛因滥用的长期影响提供了新的目标。

Project Summary/Abstract Opiate withdrawal and post-traumatic stress disorder (PTSD) frequently present together in clinical settings. Clinical data also suggests that opiate abuse is a potential risk factor for PTSD. Understanding the mechanism for co-occurrence and vulnerability to PTSD in opiate users will provide information about the consequences of opiate abuse and inform the development of interventions that mitigate both the symptoms of heroin withdrawal, a known risk factor for relapse, and heroin’s long-term effects on stress disorders. Our laboratory has identified the hippocampal mechanisms required for development of stress enhanced fear learning (SEFL), an animal model of PTSD. We established that the severe stressor in the SEFL paradigm induces dorsal hippocampal (DH) interleukin-1β (IL-1β) in astrocytes, and that directly blocking DH IL-1 signaling with IL-1 receptor antagonist (IL- 1RA) after severe stress prevents subsequent enhanced fear learning. We have developed a pre-clinical model to investigate the effect of heroin withdrawal on enhanced fear learning. We found that withdrawal from escalating heroin administration substitutes for a severe stressor in the SEFL paradigm and that heroin withdrawal similarly increases DH IL-1β and GFAP expression, a marker of astrocyte activation. Accordingly, the plan is to test the innovative unique hypothesis that heroin withdrawal also acts through hippocampal IL-1β and alterations in astrocytes that result in enhanced fear learning. Specific Aim 1 will test the hypothesis that heroin withdrawal- induced enhancement of fear learning is mediated by IL-1β in the DH. Specifically, we will determine (A) whether withdrawal-induced enhanced fear learning is associated with potentiation of IL-1β signaling specifically in astrocytes, (B) whether blockade of DH IL-1 receptors with IL-1RA during withdrawal will protect against the development of enhanced fear learning following heroin withdrawal, (C) whether DH infusion of exogenous IL- 1β will substitute for the effects of stress and/or withdrawal to induce enhanced fear learning, and (D) whether pharmacological blockade of DH IL-1 receptors during heroin withdrawal will prevent withdrawal symptoms. Predicted results are that heroin withdrawal will increase IL-1β levels, primarily in astrocytes, and that the effect of heroin withdrawal on enhanced fear learning will be blocked by IL-1RA and mimicked by infusion of IL-1β in the DH. Also, the symptoms of withdrawal will be attenuated or blocked by the administration of IL-1RA. Collectively, the results elucidate the critical role of DH IL-1 signaling in heroin withdrawal and enhanced fear learning. Specific Aim 2 will use advanced 3-D reconstruction of individual cells to conduct morphometric analysis in combination with assessment of synaptic markers (postsynaptic density 95 and Synapsin 1) to test innovative hypotheses that changes in the morphometric properties of astrocytes, and/or alterations of astrocyte/neuron interactions are associated with the effects of both the heroin withdrawal and the severe stressor used in SEFL, and contingent on IL-1 signaling. These studies test unique hypotheses regarding the underlying mechanism of the effects of heroin withdrawal, and provide new targets for mitigating the long-term effects of heroin abuse.