Ono Kenji, Fuma Kazuya, Tabata Kaori, Sawada Makoto
Department of Brain Functions, Division of Stress Adaptation and Protection, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi 464-8601, Japan.
Biochem Biophys Res Commun. 2009 Oct 23;388(3):589-94. doi: 10.1016/j.bbrc.2009.08.055. Epub 2009 Aug 14.
Magnetic resonance imaging (MRI) is a minimally invasive way to provide high spatial resolution tomograms. However, MRI has been considered to be useless for gene expression imaging compared to optical imaging. In this study, we used a ferritin reporter, binding with biogenic iron, to make it a powerful tool for gene expression imaging in MRI studies. GL261 mouse glioma cells were over-expressed with dual-reporter ferritin-DsRed under beta-actin promoter, then gene expression was observed by optical imaging and MRI in a brain tumor model. GL261 cells expressing ferritin-DsRed fusion protein showed enhanced visualizing effect by reducing T2-weighted signal intensity for in vitro and in vivo MRI studies, as well as DsRed fluorescence for optical imaging. Furthermore, a higher contrast was achieved on T2-weighted images when permeating the plasma membrane of ferritin-DsRed-expressing GL261. Thus, a ferritin expression vector can be used as an MRI reporter to monitor in vivo gene expression.
磁共振成像（MRI）是一种提供高空间分辨率断层图像的微创方法。然而，与光学成像相比，MRI一直被认为对基因表达成像无用。在本研究中，我们使用一种与生物源铁结合的铁蛋白报告基因，使其成为MRI研究中基因表达成像的有力工具。在β-肌动蛋白启动子下，用双报告基因铁蛋白-DsRed对GL261小鼠胶质瘤细胞进行过表达，然后在脑肿瘤模型中通过光学成像和MRI观察基因表达。表达铁蛋白-DsRed融合蛋白的GL261细胞在体外和体内MRI研究中通过降低T2加权信号强度以及在光学成像中通过DsRed荧光显示出增强的可视化效果。此外，当铁蛋白-DsRed表达的GL261细胞膜通透时，在T2加权图像上获得了更高的对比度。因此，铁蛋白表达载体可作为MRI报告基因用于监测体内基因表达。
