Role of circHomer1 in synaptic plasticity and cocaine-seeking behavior

circHomer1 在突触可塑性和可卡因寻求行为中的作用

• 批准号: 10164747
• 负责人: Janet L Neisewander
• 金额: $ 18.62万
• 依托单位: ARIZONA STATE UNIVERSITY-TEMPE CAMPUS
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-15 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10164747
• 关键词: Abstinence; Address; Animal Model; Antibodies; Attention; Attenuated; Back; Behavior; Binding; Biological Assay; Brain; Central Nervous System Diseases; Chronic; Cocaine; Cocaine Dependence; Coculture Techniques; Code; Corpus striatum structure; Cues; Development; Disease; Drug Addiction; Drug Modelings; Electrophysiology (science); Event; Family; Female; Functional disorder; Gene Expression; Genes; Genetic Transcription; Hippocampus (Brain); Homer 1a; Homer protein; Homologous Gene; Homologous Protein; HuD antigen; Immunoprecipitation; In Situ; Individual; Infusion procedures; Intravenous; Laboratories; Light; Measures; Mediating; Messenger RNA; Metabotropic Glutamate Receptors; MicroRNAs; Modeling; Molecular; Motivation; Mus; Neuronal Plasticity; Neurons; Nucleus Accumbens; Pharmaceutical Preparations; Play; Porifera; Preparation; Process; Property; Protein Splicing; Proteins; Quantitative Reverse Transcriptase PCR; RNA; RNA Splicing; RNA-Binding Proteins; Rattus; Receptor Signaling; Recording of previous events; Research; Reversal Learning; Role; Saline; Self Administration; Signal Transduction; Substance Use Disorder; Synapses; Synaptic plasticity; Synaptosomes; Testing; Training; Untranslated RNA; Virus; Western Blotting; Work; addiction; base; brain abnormalities; circular RNA; cocaine self-administration; cocaine use; conditioned place preference; cue reactivity; drug seeking behavior; environmental enrichment for laboratory animals; experimental study; frontal lobe; immunocytochemistry; insight; knock-down; lentiviral-mediated; mRNA Precursor; male; novel; overexpression; relapse patients; response; small hairpin RNA; synaptic function; transcription factor; treatment strategy

Brain abnormalities associated with substance use disorders (SUDs) involve long-term changes in gene expression that derail motivational circuits toward drug seeking and taking despite negative consequences. While the role of transcription factors in gene expression changes has been well established, the subsequent post-transcriptional events that result in functional change are far from understood. Recent breakthroughs suggest that circular RNAs (circRNAs) are critical in regulating post-transcriptional events. This new class of non-coding RNAs plays a critical role in brain development and synaptic function by acting as sponges for sequestering microRNAs (miRNAs) and RNA-binding proteins (RBPs), which regulate gene expression, often in a competitive manner. For instance, our laboratory has shown that the RBP, HuD, competes with miR-495 to regulate expression of addiction-related genes. Our new preliminary results demonstrate that HuD also binds to, and regulates, the expression and synaptic localization of 14 brain-specific circRNAs, including circHomer1. circHomer1 is generated from the same gene (Homer1) that generates linear Homer1b mRNA, which is also a HuD target. Importantly, Homer1 protein is involved in cocaine–induced plasticity and drug seeking via its role in regulating type I metabotropic glutamate receptor signaling and homeostatic synaptic downscaling after increased neuronal activity. We found that knockdown of circHomer1 levels increases synaptic activity and synaptic Homer1b mRNA levels. Using HuD overexpressing mice, we determined that this process requires binding of the circRNA to HuD. Furthermore, we found that circHomer1 levels in the nucleus accumbens (NAc) are decreased in mice displaying increased cocaine-seeking behavior in the conditioned place preference model. In contrast, the varying levels of operant cocaine-seeking behavior in rats living in an enriched environment (low levels) versus isolation (high levels) during forced abstinence after a history of cocaine self- administration inversely correlate with the ratios of circHomer1 to Homer1b mRNA levels in the NAc shell. Based on these results, we hypothesize that synaptic circHomer1 expression in the NAc shell regulates synaptic activity by competing with Homer1b mRNA for HuD binding, leading to downstream effects in Homer1b function that attenuate drug-seeking behavior. To test this hypothesis, we will first examine whether circHomer1 and Homer1b mRNA compete for HuD binding, transport to synapses, and the control of neuronal activity in neurons in culture. We will then evaluate the effects of lentiviral-mediated manipulations of circHomer1 levels on Homer1b mRNA synaptic levels and the modulation of operant cocaine-seeking behavior. This research will impact the field by elucidating the role of circHomer1 in the mechanisms underlying changes in cocaine-induced neuroplasticity and addiction-related behaviors. Ultimately, gaining an understanding of the molecular mechanisms underlying brain changes in SUDs will aid in developing novel treatment strategies for cocaine use disorders.

与物质使用障碍（SUD）相关的大脑异常涉及长期变化 在基因表达中， 负面后果。虽然转录因子在基因表达变化中的作用 已经很好地建立，随后的转录后事件，导致功能性 变化远未被理解。最近的突破表明，环状RNA（circRNA） 在调节转录后事件中至关重要。这类新的非编码RNA发挥着 在大脑发育和突触功能中起着关键作用， 调节基因表达的微小RNA（miRNAs）和RNA结合蛋白（RBP）通常 以竞争的方式。例如，我们的实验室已经表明，RBP，HUD， 与miR-495一起调节成瘾相关基因的表达。我们新的初步结果 证明HuD也结合并调节以下蛋白的表达和突触定位： 14种脑特异性circRNA，包括circHomer 1。circHomer 1是由同一个基因产生的， （Homer 1），其产生线性Homer 1b mRNA，其也是HuD靶标。重要的是， Homer 1蛋白通过其在可卡因诱导的可塑性和药物寻找中的作用参与可卡因诱导的可塑性和药物寻找。 调节I型代谢型谷氨酸受体信号传导和稳态突触 神经元活动增加后缩小比例。我们发现敲低circHomer 1水平 增加突触活性和突触Homer 1b mRNA水平。使用HuD过度表达 在小鼠中，我们确定这个过程需要circRNA与HuD的结合。而且我们 研究发现，在小鼠的丘脑核（NAc）中的circHomer 1水平降低， 在条件位置偏好模型中增加可卡因寻求行为。而反观 生活在丰富环境中的大鼠中不同水平的操作性可卡因寻求行为（低 水平）与隔离（高水平）在可卡因自我- 给药后，与circHomer 1与Homer 1b mRNA水平的比值呈负相关。 NAc外壳。基于这些结果，我们假设突触circHomer 1在海马中的表达， NAc壳通过与Homer 1b mRNA竞争HuD结合来调节突触活性， 导致Homer 1b功能的下游效应，减弱药物寻求行为。到 为了验证这一假设，我们将首先检查circHomer 1和Homer 1b mRNA是否竞争 HuD结合、向突触的转运以及对培养的神经元中的神经元活性的控制。 然后，我们将评估慢病毒介导的circHomer 1水平操纵对 Homer 1b mRNA突触水平和操作性可卡因寻求行为的调制。这 研究将通过阐明circHomer 1在机制中的作用来影响该领域 可卡因诱导的神经可塑性和成瘾相关行为的潜在变化。 最终，了解大脑变化的分子机制， SUD将有助于开发可卡因使用障碍的新治疗策略。