Neuronal Circuits and Molecular Mechanisms Underlying Early Social Isolation-Potentiated Heroin Seeking

摘要 海洛因成瘾以强迫性渴求、寻求毒品和复发为特征，是 被认为是最具问题的公共卫生问题之一。海洛因复吸受以下因素的影响很大 压力。人体研究表明，暴露在生活压力源下与强迫性药物滥用和 在禁欲期间再次吸毒。更重要的是，早期生活中的环境压力 与形成成瘾的更大风险和更容易复发有关。早期的社会孤立(在 青春期作为一种广泛使用的早期生活应激模型之一，会导致许多行为 与精神健康问题有关的异常，包括复发的可能性增加。我的初选 数据证实，ESI增强了强制戒除海洛因后线索诱导的海洛因寻求 管理(SA)。然而，其潜在的神经生物学机制在很大程度上还没有得到充分的研究。 前额叶皮质(PFC)参与药物复发的调控。已发现PFC功能不全 阿片类药物滥用者。临床前研究表明，PFC投射到皮质下区域，如NAC和 VTA是海洛因复发的关键因素。由于ESI导致了不可逆的PFC突触功能障碍，很可能是 ESI通过加剧PFC故障来加强海洛因寻找。此外，由于功率因数校正的异构性 投射神经元(PFC-VTA和PFC-NAC投射具有不同的分布和分子特征)， 目前尚不清楚海洛因复发易感性的神经元回路特异性分子机制是什么。 因此，我的中心假设是PFC(PFC-VTA/PFC-NAC)投射神经元功能低下 参与ESI-增强海洛因寻找，并且这种效应伴随着基因转录变化 在PFC-VTA和/或PFC-NAC投射神经元内。 为了验证我的假设，我将结合最先进的电生理学、化学遗传学策略 (DREADDS)和投影特异性分子图谱(TRAP[翻译核糖体亲和纯化]) 把科技引入我的书房。我建议测量PFC-NAC和PFC-VTA的兴奋性突触传递 海洛因SA强制戒断后的神经元投射。将使用化学遗传工具来测试 PFC-VTA和PFC-NAC投射神经元在ESI强化海洛因寻找中的作用诱捕法 (使用GFPL10转基因小鼠)将被用于分离投射特定神经元以用于rna-seq鉴定。 ESI增强海洛因寻找的潜在分子机制。完成我的研究计划和 培训计划将使我能够独立追求我的长期职业目标：学习神经元电路特异性 海洛因的分子机制寻求最终促进药物治疗的发展 海洛因复发。

Abstract Heroin addiction is characterized by compulsive craving, drug seeking and re-occurrence of relapse, and is considered to be one of the most problematic public health concerns. Heroin relapse is significantly affected by stress. Human studies suggest that exposure to life stressors is correlated with compulsive drug abuse and relapse to drugs during periods of abstinence. More importantly, environmental stress during early life is related to bigger risk for developing addiction and increased relapse vulnerability. Early social isolation (during adolescence, ESI), as one of the widely used models for early life stress, causes many behavioral abnormalities that related to mental health issues including increased vulnerability for relapse. My preliminary data confirmed that ESI potentiates cue-induced heroin seeking after forced abstinence from heroin self- administration (SA). However, the underlying neurobiological mechanisms are largely understudied. Prefrontal cortex (PFC) is involved in the regulation of drug relapse. PFC hypofunction has been identified in opioid abusers. Preclinical studies indicate that PFC, which projects to subcortical regions such as NAc and VTA, is critical for heroin relapse. As ESI induces irreversible synaptic dysfunction in the PFC, it is likely that ESI potentiates heroin seeking by exacerbating PFC malfunction. Moreover, due to the heterogeneous of PFC projecting neurons (PFC-VTA and PFC-NAc projection have distinct distribution and molecular signatures), it remains unclear what are the neuronal circuit-specific molecular mechanisms for heroin relapse vulnerability. Therefore, my central hypothesis is that hypofunction of PFC (PFC-VTA/PFC-NAc) projecting neurons is involved in ESI-potentiates heroin seeking, and this effect is accompanied by gene transcriptional changes within the PFC-VTA and/or PFC-NAc projecting neurons. To test my hypothesis, I will incorporate state-of-the-art electrophysiology, chemogenetic strategies (DREADDs), and projection-specific molecular profiling (TRAP [translating ribosome affinity purification]) technologies into my study. I propose to measure excitatory synaptic transmission in PFC-NAc and PFC-VTA projecting neurons after forced abstinence from heroin SA. Chemogenetic tools will be used to test the functional role of PFC-VTA and PFC-NAc projecting neurons in ESI-intensified heroin seeking. TRAP methods (using GFPL10 transgenic mice) will be applied to isolate projection-specific neurons for RNA-seq to identify potential molecular mechanisms for ESI-potentiated heroin seeking. Fulfillment of my Research Plan and Training Plan will allow me to independently pursue my long-term career goals: study neuronal circuit-specific molecular mechanisms for heroin seeking to ultimately contribute to the development of pharmacotherapies for heroin relapse.