MR Assessment of Altered Cerebral Gene Expression after Amphetamine Exposure

描述（由申请人提供）：本拟议项目旨在验证和完善一种新型MRI技术，该技术使用靶向MR造影剂探针检测活体动物暴露于安非他明导致的内源性基因表达改变。我们将在C57 Black 6小鼠中使用成瘾的动物模型。在这个项目中要研究的目标是转录因子fosB和激活蛋白1（AP-1）的mRNA，其表达的改变与药物成瘾密切相关。 最新的分子成像方法检测细胞表面蛋白作为基因表达的标志物。我们提出的技术检测基因表达的细胞内产物，例如mRNA及其产物，它们可能在活小鼠的大脑中具有DNA结合能力。该方法使用具有针对靶mRNA的反义序列的DNA或具有用于AP-1结合的共有序列的DNA。在初步研究中，我们用MR造影剂标记这些DNA，并在概念验证研究中表明，该探针能够在急性安非他明注射后使用MRI报告c-fos mRNA升高的活体动物。 我们的目标是扩展和提高这项技术的灵敏度，并建立MR信号和细胞内靶点的组织学评估之间的相关性。通过实现这些目标，我们将能够应用这种新的MR技术作为定量工具，用于检测其他基因的内源性基因表达，如环AMP反应元件（CREB）和与药物成瘾有关的其他基因表达产物。项目叙述： 在这个项目中，我们将扩展和完善一种新的磁共振成像（MRI）技术，我们已经开发了检测受成瘾药物影响的活体动物大脑中改变的基因表达。该项目的目标是使这项技术成为定量工具来测量大脑中的内源性基因表达。这种增强将使人们更接近于对药物滥用和成瘾患者发生的神经生理事件进行实时分析。

DESCRIPTION (provided by applicant): This proposed project aims to validate and refine a novel MRI technique that uses targeting MR contrast probes to detect altered endogenous gene expression resulting from amphetamine exposure in living animals. We will use an animal model of addiction in C57Black6 mice. The targets to be investigated in this project are mRNA of a transcription factor fosB and the activator protein 1 (AP-1) whose altered expression is strongly implicated in drug addiction. Most current molecular imaging methods detect cell surface proteins as markers of gene expression. Our proposed technique detects intracellular products of gene expression, such as mRNA and its products that may have DNA binding ability in the brains of living mice. This method uses DNA with antisense sequence to the target mRNA or DNA with consensus sequence for AP-1 binding. In preliminary studies, we labeled these DNA with MR contrast agent and showed in a proof-of-concept study that the probe is capable of reporting elevation of c-fos mRNA live animals using MRI after acute amphetamine injection. Our goals are to extend and improve the sensitivity of this technique and establish the correlate between MR signal and histological assessment of intracellular targets. By achieving these goals, we will be able to apply this novel MR technique as a quantitative tool for the detection of endogenous gene expression of other genes such as cyclic AMP responsive elements (CREB) and a host of other products of gene expression that are implicated in drug addiction.Project Narrative: In this project, we will extend and refine a novel Magnetic Resonance Imaging (MRI) technique that we have developed to detect altered gene expression in the brains of live animal affected by addictive drugs. The goal of this project is to make this technique a quantitative tool to measure endogenous gene expression in the brains. Such enhancement will bring a step closer to real-time analysis of neurophysiologic events that occur in patients with substance abuse and addiction.