MS-1 magA: Revisiting Its Efficacy as a Reporter Gene for MRI.
Bacterial genes involved in the biomineralization of magnetic nanoparticles in magnetotactic bacteria have recently been proposed as reporters for magnetic resonance imaging (MRI). In such systems, the expression of the bacterial genes in mammalian cells purportedly leads to greater concentrations of intracellular iron or the biomineralization of iron oxides, thus leading to an enhancement in relaxation rate that is detectable via MRI. Here, we show that the constitutive expression of the magA gene from Magnetospirillum magnetotacticum is tolerated by human embryonic kidney (HEK) cells but induces a strong toxic effect in murine mesenchymal/stromal cells and kidney-derived stem cells, severely restricting its effective use as a reporter gene for stem cells. Although it has been suggested that magA is involved in iron transport, when expressed in HEK cells, it does not affect the transcription of endogenous genes related to iron homeostasis. Furthermore, the magA-induced enhancement in iron uptake in HEK cells is insignificant, suggesting this gene is a poor reporter even for cell types that can tolerate its expression. We suggest that the use of magA for stem cells should be approached with caution, and its efficacy as a reporter gene requires a careful assessment on a cell-by-cell basis.
Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, United Kingdom.
Sofia M
SM
Pereira
Centre for Imaging Sciences, University of Manchester, Oxford Road, Manchester, United Kingdom.
Steve R
SR
Williams
Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, United Kingdom.
Patricia
P
Murray
Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, United Kingdom taylora@liverpool.ac.uk.
Arthur
A
Taylor
D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology*; D027682:Cation Transport Proteins / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003287:Contrast Media; D017930:Genes, Reporter; D057809:HEK293 Cells; D006801:Humans; D007501:Iron / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects*; D051379:Mice
D001426:Bacterial Proteins; D027682:Cation Transport Proteins; D003287:Contrast Media; C097085:MagA protein, Magnetospirillum; D007501:Iron
cell tracking; cellular imaging and trafficking; magnetic resonance imaging; viral vector