MR Assessment of Altered Cerebral Gene Expression after Amphetamine Exposure

描述(申请人提供)：这项拟议的项目旨在验证和改进一种新的磁共振成像技术，该技术使用靶向磁共振对比探针来检测由于接触苯丙胺而导致的活体动物内源性基因表达的变化。我们将使用C57Black6小鼠的成瘾动物模型。本项目要研究的目标是转录因子FosB和激活蛋白1(AP-1)的mRNA，它们的表达变化与药物成瘾密切相关。 大多数目前的分子成像方法检测细胞表面蛋白作为基因表达的标志。我们建议的技术检测细胞内基因表达的产物，如在活着的小鼠大脑中可能具有DNA结合能力的mRNA及其产物。该方法利用具有反义序列的DNA与靶mRNA或具有一致序列的DNA进行AP-1结合。在初步研究中，我们用磁共振造影剂标记了这些DNA，并在概念验证研究中表明，该探针能够在急性注射苯丙胺后使用MRI报告活体动物c-fos mRNA的升高。 我们的目标是扩展和提高这项技术的灵敏度，并建立MR信号与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颖的磁共振技术作为一种定量工具来检测其他基因的内源性基因表达，如环磷酸腺苷反应元件(CREB)和许多与药物成瘾有关的其他基因表达产物。 在这个项目中，我们将扩展和改进我们开发的一种新的磁共振成像(MRI)技术，以检测受成瘾药物影响的活动物大脑中基因表达的变化。该项目的目标是使这项技术成为测量大脑内源性基因表达的定量工具。这种增强将使对药物滥用和成瘾患者发生的神经生理事件的实时分析更近一步。

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.