The ability to non-invasively image the duration and location of gene expression in vivo is important for the future of biomedical research and molecular medicine. The goal of this application is to develop a general purpose MRI reporter gene cassette that can be used in a variety of molecular imaging applications. Recent results from our laboratory demonstrate that vectors encoding metalloprotein reporters delivered into the living mouse brain can elicit potent contrast in MR images. The reporter protein is made superparamagnetic as the cell sequesters endogenous iron from the organism. Our approach is unique because the cell constructs the MRI contrast agent in situ by genetic means. No bulky-metal complex is required, thereby simplifying intracellular delivery. Our proposal consists of three Specific Aims: (1) we will design second generation MRI reporters for improved sensitivity and minimal reporter sequence length. MRI reporters will be incorporated into replication-defective viral vectors including adenovirus, herpes simplex virus, and vesicular stomatitis virus, for subsequent cell culture and in vivo studies; (2) using the viral vectors we will perform extensive in vitro analyses of the chemical, biochemical, biophysical and toxicological properties of the reporters in established cell lines; (3) we will demonstrate proof-of-principle in vivo by longitudinally imaging the MRI reporters in the CNS of mice. We will quantitatively evaluate their contrasting effects in different tissues via focal injections and by targeting their expression using tissue-specific promoters. Finally, we will look for evidence of pathologic changes in reporter-transduced brain tissues using an array of neuropathological markers. Overall, this platform technology can be adapted to examine gene expression in many tissue types, and thus there are a large number of potential in vivo applications. Examples include preclinical testing of gene therapeutics, such as for the treatment of metastatic disease, and use in transgenic models for drug development. Thus, there is high relevance to the mission of the NIH. Lay Summary - Tools that enable one to visualize gene expression within the living organism are of fundamental importance to the future of medicine and biomedical research. The emerging field of genetic medicine requires non-invasive imaging methods that can indicate if the therapeutic genes have been delivered to the correct cells and if the desired proteins have been made. Towards this goal, our project will develop new technologies to visualize gene expression in vivo using conventional magnetic resonance imaging (MRI) scanners.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
5R01EB005740-02
Application #
7120551
Study Section
Microscopic Imaging Study Section (MI)
Program Officer
Mclaughlin, Alan Charles
Project Start
2005-09-07
Project End
2009-06-30
Budget Start
2006-07-01
Budget End
2007-06-30
Support Year
2
Fiscal Year
2006
Total Cost
$320,891
Indirect Cost
Name
Carnegie-Mellon University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
052184116
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Iordanova, Bistra; Hitchens, T Kevin; Robison, Clinton S et al. (2013) Engineered mitochondrial ferritin as a magnetic resonance imaging reporter in mouse olfactory epithelium. PLoS One 8:e72720
Iordanova, B; Goins, W F; Clawson, D S et al. (2013) Quantification of HSV-1-mediated expression of the ferritin MRI reporter in the mouse brain. Gene Ther 20:589-96
Iordanova, Bistra; Ahrens, Eric T (2012) In vivo magnetic resonance imaging of ferritin-based reporter visualizes native neuroblast migration. Neuroimage 59:1004-12
Mills, Parker H; Hitchens, T Kevin; Foley, Lesley M et al. (2012) Automated detection and characterization of SPIO-labeled cells and capsules using magnetic field perturbations. Magn Reson Med 67:278-89
Iordanova, B; Robison, C S; Goins, W F et al. (2010) Single chain ferritin chimera as an improved MRI gene reporter. Prilozi 31:151-5
Iordanova, Bistra; Robison, Clinton S; Ahrens, Eric T (2010) Design and characterization of a chimeric ferritin with enhanced iron loading and transverse NMR relaxation rate. J Biol Inorg Chem 15:957-65
Mills, Parker H; Ahrens, Eric T (2009) Enhanced positive-contrast visualization of paramagnetic contrast agents using phase images. Magn Reson Med 62:1349-55
Mills, Parker H; Wu, Yi-Jen L; Ho, Chien et al. (2008) Sensitive and automated detection of iron-oxide-labeled cells using phase image cross-correlation analysis. Magn Reson Imaging 26:618-28