In vivo Profiling of Glial and Neuronal Activities in Psychostimulant Abuse

描述（由申请人提供）：精神兴奋剂滥用中神经胶质和神经元活动的体内分析（PI: Christina H Liu, PhD）药物成瘾是一种慢性脑部疾病，严重阻碍了我们社会许多成员的生产力。滥用最多的药物之一是安非他明。大多数关于安非他明的神经科学研究都集中在神经元对慢性药物暴露的形态学和分子适应上。来自细胞培养或脑切片制备的电生理数据表明，药物滥用的一个重要组成部分是在反复暴露于安非他明引起的神经元激活过程中，胶质细胞和神经元之间发生的相互作用。虽然我们知道神经胶质细胞对神经元的存活至关重要，为神经元提供关键的支持、营养和毒素清除，但我们对神经胶质细胞在药物成瘾中的作用的理解非常有限。为了克服这一限制，我们开发了一种新的体内探针，利用磁共振成像（MRI）在暴露于安非他明后的活脑中观察神经元和神经胶质中基因活动的变化。我们已经证明了这种方法对表达不同但特定基因活动的细胞的歧视的效用；即，cfos信使RNA （mRNA）从基于神经胶质的GFAP mRNA中以神经元为基础的升高。由于我们的检测技术不需要使用尸体样本，因此我们能够研究暴露于药物期间和之后不同大脑基因活动的纵向剖面。在这里，我们的目的是研究活的C57Black6小鼠在苯丙胺致敏过程中的基因激活，包括反复使用、戒断和再次暴露于苯丙胺。我们将利用我们的新技术，使用mrna靶向MR对比探针来检测神经元和神经胶质中因安非他明暴露而导致的内源性基因活性的改变。本项目拟研究的靶点是胶质纤维酸性蛋白（GFAP）和神经元cFos蛋白的mrna。我们这个项目的目标是利用这种新的MRI技术来增强对神经胶质细胞和神经元细胞在安非他明暴露的不同阶段之间相互作用的理解。我们提出以下具体目标：(1)确定MRI探针在活脑中的最佳剂量和保留谱；(2)测定安非他明不同暴露阶段小鼠脑内胶质细胞和神经元细胞的基因活性谱；(3)探讨神经元介导的神经胶质反应在苯丙胺成瘾表型发展中的作用。公共卫生相关性：在这个项目中，我们将利用我们开发的一种新型磁共振成像（MRI）技术来检测受成瘾性药物影响的活体动物神经元和神经胶质中基因表达的改变。该项目的目的是加强目前的理解之间的相互作用，胶质细胞和神经元细胞在安非他明暴露的不同阶段。这种增强将使实时分析发生在药物滥用和成瘾患者身上的神经生理事件更近一步。

DESCRIPTION (provided by applicant): In vivo profiling of glial and neuronal activities in psychostimulant abuse (PI: Christina H Liu, PhD) Drug addiction is a chronic brain disorder that severely hampers productivity of many members of our society. One of the most used drugs of abuse is amphetamine. Most neuroscience studies on amphetamine have focused on the morphological and molecular adaptations of neurons in response to chronic drug exposure. Electrophysiological data from cell cultures or brain slice preparations show that an important component of drug abuse is the interaction that occurs between glia and neurons during neuronal activations arising from repeat exposure to amphetamine. Although we know that glial cells are essential to the survival of neurons, providing critical support, nutrition, and toxin clearance to the neurons, our understanding of the role of glia in drug addiction is very limited. To overcome this limitation, we have developed a novel in vivo probe to visualize the changes in gene activities in neurons and glia, using magnetic resonance imaging (MRI) in live brains after exposure to amphetamine. We have demonstrated the utility of this method for discrimination of cells that express different but specific gene activities; i.e., neuronal-based elevation of cfos messenger RNA (mRNA) from glia-based GFAP mRNA. Because our detection technique does not require the use of postmortem samples, we are able to study the longitudinal profiles of different cerebral gene activities during and after exposure to drugs. Here, we aim to study gene activation during amphetamine sensitization in living C57Black6 mice, which involves repeated usage of, abstinence from, and re-exposure to the drug. We will utilize our novel technique that uses mRNA-targeted MR contrast probes to detect altered endogenous gene activities that result from amphetamine exposure in neurons and glia. The targets to be investigated in this project are mRNAs of glial fibrillary acidic protein (GFAP) and neuronal cFos protein. Our goals for this project are to use this novel MRI technique to enhance current understanding of the interactions between glial and neuronal cells at different stages of amphetamine exposure. We propose the following specific aims: (1) determine the optimal dosage and retention profiles of MRI probes in live brains; (2) determine the gene activity profiles of glial and neuronal cells in mouse brains in vivo after amphetamine, at different stages of exposure; and (3) explore the neuron-mediated glial response in the development of the amphetamine addiction phenotype. PUBLIC HEALTH RELEVANCE: In this project, we will utilize a novel Magnetic Resonance Imaging (MRI) technique that we have developed to detect altered gene expression in neurons and glia of live animal affected by addictive drugs. The goals of this project are to enhance current understanding of the interaction between glial and neuronal cells at different stages of amphetamine exposure. Such enhancement will bring a step closer to real-time analysis of neurophysiologic events that occur in patients with substance abuse and addiction.