Biomolecular Pharmacology Training Program, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118.
Laboratory of Addiction Genetics, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118.
J Neurosci. 2020 Jan 2;40(1):107-130. doi: 10.1523/JNEUROSCI.1808-19.2019. Epub 2019 Nov 8.
Individual variation in the addiction liability of amphetamines has a heritable genetic component. We previously identified (heterogeneous nuclear ribonucleoprotein H1) as a quantitative trait gene underlying decreased methamphetamine-induced locomotor activity in mice. Here, we showed that mice (both females and males) with a heterozygous mutation in the first coding exon of (H1) showed reduced methamphetamine reinforcement and intake and dose-dependent changes in methamphetamine reward as measured via conditioned place preference. Furthermore, H1 mice showed a robust decrease in methamphetamine-induced dopamine release in the NAc with no change in baseline extracellular dopamine, striatal whole-tissue dopamine, dopamine transporter protein, dopamine uptake, or striatal methamphetamine and amphetamine metabolite levels. Immunohistochemical and immunoblot staining of midbrain dopaminergic neurons and their forebrain projections for TH did not reveal any major changes in staining intensity, cell number, or forebrain puncta counts. Surprisingly, there was a twofold increase in hnRNP H protein in the striatal synaptosome of H1 mice with no change in whole-tissue levels. To gain insight into the mechanisms linking increased synaptic hnRNP H with decreased methamphetamine-induced dopamine release and behaviors, synaptosomal proteomic analysis identified an increased baseline abundance of several mitochondrial complex I and V proteins that rapidly decreased at 30 min after methamphetamine administration in H1 mice. In contrast, the much lower level of basal synaptosomal mitochondrial proteins in WT mice showed a rapid increase. We conclude that H1 decreases methamphetamine-induced dopamine release, reward, and reinforcement and induces dynamic changes in basal and methamphetamine-induced synaptic mitochondrial function. Methamphetamine dependence is a significant public health concern with no FDA-approved treatment. We discovered a role for the RNA binding protein hnRNP H in methamphetamine reward and reinforcement. mutation also blunted methamphetamine-induced dopamine release in the NAc, a key neurochemical event contributing to methamphetamine addiction liability. Finally, mutants showed a marked increase in basal level of synaptosomal hnRNP H and mitochondrial proteins that decreased in response to methamphetamine, whereas WT mice showed a methamphetamine-induced increase in synaptosomal mitochondrial proteins. Thus, we identified a potential role for hnRNP H in basal and dynamic mitochondrial function that informs methamphetamine-induced cellular adaptations associated with reduced addiction liability.
安非他命成瘾性的个体差异具有遗传因素。我们之前发现核不均一核糖核蛋白 H1（heterogeneous nuclear ribonucleoprotein H1，H1）是一个数量性状基因，它可以降低小鼠对甲基苯丙胺诱导的运动活性。在这里，我们表明，H1 基因第一个编码外显子杂合突变的小鼠（雌雄均有）表现出减少的甲基苯丙胺强化作用和摄入作用，以及通过条件性位置偏好测量的药物奖励的剂量依赖性变化。此外，H1 小鼠的 NAc 中，甲基苯丙胺诱导的多巴胺释放明显减少，而基础细胞外多巴胺、纹状体全组织多巴胺、多巴胺转运蛋白蛋白、多巴胺摄取或纹状体中甲基苯丙胺和苯丙胺代谢物水平没有变化。中脑多巴胺能神经元及其投射到前脑的 TH 的免疫组织化学和免疫印迹染色没有显示出染色强度、细胞数量或前脑 puncta 计数的任何重大变化。令人惊讶的是，H1 小鼠纹状体突触小体中的 hnRNP H 蛋白增加了两倍，而整个组织水平没有变化。为了深入了解将突触 hnRNP H 与减少的甲基苯丙胺诱导的多巴胺释放和行为联系起来的机制，突触体蛋白质组分析发现，在 H1 小鼠中，几种线粒体复合物 I 和 V 蛋白的基础水平增加，在给予甲基苯丙胺 30 分钟后迅速减少。相比之下，WT 小鼠中基础水平较低的突触体线粒体蛋白迅速增加。我们得出结论，H1 减少了甲基苯丙胺诱导的多巴胺释放、奖励和强化作用，并诱导了基础和甲基苯丙胺诱导的突触线粒体功能的动态变化。美沙酮依赖是一个严重的公共卫生问题，没有 FDA 批准的治疗方法。我们发现 RNA 结合蛋白 hnRNP H 在美沙酮奖励和强化中起作用。H1 突变也减弱了 NAc 中甲基苯丙胺诱导的多巴胺释放，这是导致美沙酮成瘾性的关键神经化学事件。最后，H1 突变体显示出基础突触小体 hnRNP H 和线粒体蛋白水平的显著增加，这些蛋白在给予甲基苯丙胺后减少，而 WT 小鼠显示出突触小体线粒体蛋白的甲基苯丙胺诱导增加。因此，我们确定了 hnRNP H 在基础和动态线粒体功能中的潜在作用，这为减少成瘾性的与甲基苯丙胺诱导的细胞适应相关的信息提供了信息。
