A new transgene reporter for in vivo magnetic resonance imaging

We report a new platform technology for visualizing transgene expression in living subjects using magnetic resonance imaging (MRI). Using a vector, we introduced an MRI reporter, a metalloprotein from the ferritin family, into specific host tissues. The reporter is made superparamagnetic as the cell sequesters endogenous iron from the organism. In this new approach, the cells construct the MRI contrast agent in situ using genetic instructions introduced by the vector. No exogenous metal-complexed contrast agent is required, thereby simplifying intracellular delivery. We used a replication-defective adenovirus vector to deliver the ferritin transgenes. Following focal inoculation of the vector into the mouse brain, we monitored the reporter activity using in vivo time-lapse MRI. We observed robust contrast in virus-transduced neurons and glia for several weeks. This technology is adaptable to monitor transgene expression in vivo in many tissue types and has numerous biomedical applications, such as visualizing preclinical therapeutic gene delivery.

[1]  D. Pouliquen,et al.  Biodegradation of magnetite dextran nanoparticles in the rat. A histologic and biophysical study. , 1994, Laboratory investigation; a journal of technical methods and pathology.

[2]  J. Bulte,et al.  Preparation of magnetically labeled cells for cell tracking by magnetic resonance imaging. , 2004, Methods in enzymology.

[3]  J A Frank,et al.  Magnetoferritin: Characterization of a novel superparamagnetic MR contrast agent , 1994, Journal of magnetic resonance imaging : JMRI.

[4]  H. Sweeney,et al.  Noninvasive measurement of gene expression in skeletal muscle. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[5]  M. Dhenain,et al.  T2-weighted MRI Studies of Mouse Lemurs: A Primate Model of Brain Aging , 1997, Neurobiology of Aging.

[6]  E T Ahrens,et al.  Receptor‐mediated endocytosis of iron‐oxide particles provides efficient labeling of dendritic cells for in vivo MR imaging , 2003, Magnetic resonance in medicine.

[7]  R. Weissleder,et al.  In vivo high resolution three-dimensional imaging of antigen-specific cytotoxic T-lymphocyte trafficking to tumors. , 2003, Cancer research.

[8]  R A Brooks,et al.  Iron uptake by ferritin: NMR relaxometry studies at low iron loads. , 1998, Journal of inorganic biochemistry.

[9]  A. Koretsky,et al.  NMR detection of creatine kinase expressed in liver of transgenic mice: determination of free ADP levels. , 1990, Proceedings of the National Academy of Sciences of the United States of America.

[10]  Rika Takikawa,et al.  [In-vivo visualization of gene expression using magnetic resonance imaging]. , 2007, Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme.

[11]  S. Cherry,et al.  Imaging adenoviral-directed reporter gene expression in living animals with positron emission tomography. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[12]  C. Beaumont,et al.  Transient overexpression of human H- and L-ferritin chains in COS cells. , 1998, The Biochemical journal.

[13]  Chien Ho,et al.  Intracellular labeling of T‐cells with superparamagnetic contrast agents , 1993, Magnetic resonance in medicine.

[14]  P. Arosio,et al.  Production and characterization of recombinant heteropolymers of human ferritin H and L chains. , 1993, The Journal of biological chemistry.

[15]  A. Albertini,et al.  Overexpression of Wild Type and Mutated Human Ferritin H-chain in HeLa Cells , 2000, The Journal of Biological Chemistry.

[16]  J. Bulte,et al.  T1 and T2 of ferritin solutions: Effect of loading factor , 1996, Magnetic resonance in medicine.

[17]  M. Neeman,et al.  Ferritin effect on the transverse relaxation of water: NMR microscopy at 9.4 T , 1996, Magnetic resonance in medicine.

[18]  K. Surry,et al.  Temperature dosimetry using MR relaxation characteristics of poly(vinyl alcohol) cryogel (PVA‐C) , 2001, Magnetic resonance in medicine.

[19]  Anna Moore,et al.  In vivo magnetic resonance imaging of transgene expression , 2000, Nature Medicine.

[20]  David Katz,et al.  The relation between brain iron and NMR relaxation times: An in vitro study , 1996, Magnetic resonance in medicine.

[21]  S. Welch.  Transferrin: The Iron Carrier , 1992 .

[22]  C. Contag,et al.  Advances in in vivo bioluminescence imaging of gene expression. , 2002, Annual review of biomedical engineering.

[23]  P. Harrison,et al.  Evidence of H- and L-chains have co-operative roles in the iron-uptake mechanism of human ferritin. , 1992, The Biochemical journal.

[24]  R D Klausner,et al.  Receptor-mediated endocytosis of transferrin in K562 cells. , 1983, The Journal of biological chemistry.

[25]  Joseph L. Kirschvink,et al.  Magnetotactic bacteria and single-domain magnetite in hemipelagic sediments , 1986, Nature.

[26]  C. Beaumont,et al.  H-ferritin subunit overexpression in erythroid cells reduces the oxidative stress response and induces multidrug resistance properties. , 1999, Blood.