Biophysical features of MagA expression in mammalian cells: implications for MRI contrast
We compared overexpression of the magnetotactic bacterial gene MagA with the modified mammalian ferritin genes HF+LF, in which both heavy and light subunits lack iron response elements. Whereas both expression systems have been proposed for use in non-invasive, magnetic resonance (MR) reporter gene...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2014-02-01
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| Series: | Frontiers in Microbiology |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fmicb.2014.00029/full |
| _version_ | 1818238377113157632 |
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| author | Anindita eSengupta Anindita eSengupta Anindita eSengupta Karina eQuiaoit Karina eQuiaoit Karina eQuiaoit R Terry Thompson R Terry Thompson Frank S Prato Frank S Prato Neil eGelman Neil eGelman Donna E Goldhawk Donna E Goldhawk Donna E Goldhawk |
| author_facet | Anindita eSengupta Anindita eSengupta Anindita eSengupta Karina eQuiaoit Karina eQuiaoit Karina eQuiaoit R Terry Thompson R Terry Thompson Frank S Prato Frank S Prato Neil eGelman Neil eGelman Donna E Goldhawk Donna E Goldhawk Donna E Goldhawk |
| author_sort | Anindita eSengupta |
| collection | DOAJ |
| description | We compared overexpression of the magnetotactic bacterial gene MagA with the modified mammalian ferritin genes HF+LF, in which both heavy and light subunits lack iron response elements. Whereas both expression systems have been proposed for use in non-invasive, magnetic resonance (MR) reporter gene expression, limited information is available regarding their relative potential for providing gene-based contrast. Measurements of MR relaxation rates in these expression systems are important for optimizing cell detection and specificity, for developing quantification methods, and for refinement of gene-based iron contrast using magnetosome associated genes. We measured the total transverse relaxation rate (R2*), its irreversible and reversible components (R2 and R2′, respectively) and the longitudinal relaxation rate (R1) in MDA-MB-435 tumor cells. Clonal lines overexpressing MagA and HF+LF were cultured in the presence and absence of iron supplementation, and mounted in a spherical phantom for relaxation mapping at 3 Tesla. In addition to MR measures, cellular changes in iron and zinc were evaluated by inductively-coupled plasma mass spectrometry, in ATP by luciferase bioluminescence and in transferrin receptor by Western blot. Only transverse relaxation rates were significantly higher in iron-supplemented, MagA- and HF+LF-expressing cells compared to non-supplemented cells and the parental control. R2* provided the greatest absolute difference and R2′ showed the greatest relative difference, consistent with the notion that R2′ may be a more specific indicator of iron-based contrast than R2, as observed in brain tissue. Iron supplementation of MagA- and HF+LF-expressing cells increased the iron/zinc ratio approximately 20-fold, while transferrin receptor expression decreased approx. 10-fold. Level of ATP was similar across all cell types and culture conditions. These results highlight the potential of magnetotactic bacterial gene expression for improving MR contrast. |
| first_indexed | 2024-12-12T12:40:41Z |
| format | Article |
| id | doaj.art-bbf48e4f1d864dd6895e6d4e3eff93eb |
| institution | Directory Open Access Journal |
| issn | 1664-302X |
| language | English |
| last_indexed | 2024-12-12T12:40:41Z |
| publishDate | 2014-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Microbiology |
| spelling | doaj.art-bbf48e4f1d864dd6895e6d4e3eff93eb2022-12-22T00:24:14ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2014-02-01510.3389/fmicb.2014.0002968258Biophysical features of MagA expression in mammalian cells: implications for MRI contrastAnindita eSengupta0Anindita eSengupta1Anindita eSengupta2Karina eQuiaoit3Karina eQuiaoit4Karina eQuiaoit5R Terry Thompson6R Terry Thompson7Frank S Prato8Frank S Prato9Neil eGelman10Neil eGelman11Donna E Goldhawk12Donna E Goldhawk13Donna E Goldhawk14Lawson Health Research InstituteWestern UniversityCollaborative Graduate Program in Molecular ImagingLawson Health Research InstituteWestern UniversityCollaborative Graduate Program in Molecular ImagingLawson Health Research InstituteWestern UniversityLawson Health Research InstituteWestern UniversityLawson Health Research InstituteWestern UniversityLawson Health Research InstituteWestern UniversityCollaborative Graduate Program in Molecular ImagingWe compared overexpression of the magnetotactic bacterial gene MagA with the modified mammalian ferritin genes HF+LF, in which both heavy and light subunits lack iron response elements. Whereas both expression systems have been proposed for use in non-invasive, magnetic resonance (MR) reporter gene expression, limited information is available regarding their relative potential for providing gene-based contrast. Measurements of MR relaxation rates in these expression systems are important for optimizing cell detection and specificity, for developing quantification methods, and for refinement of gene-based iron contrast using magnetosome associated genes. We measured the total transverse relaxation rate (R2*), its irreversible and reversible components (R2 and R2′, respectively) and the longitudinal relaxation rate (R1) in MDA-MB-435 tumor cells. Clonal lines overexpressing MagA and HF+LF were cultured in the presence and absence of iron supplementation, and mounted in a spherical phantom for relaxation mapping at 3 Tesla. In addition to MR measures, cellular changes in iron and zinc were evaluated by inductively-coupled plasma mass spectrometry, in ATP by luciferase bioluminescence and in transferrin receptor by Western blot. Only transverse relaxation rates were significantly higher in iron-supplemented, MagA- and HF+LF-expressing cells compared to non-supplemented cells and the parental control. R2* provided the greatest absolute difference and R2′ showed the greatest relative difference, consistent with the notion that R2′ may be a more specific indicator of iron-based contrast than R2, as observed in brain tissue. Iron supplementation of MagA- and HF+LF-expressing cells increased the iron/zinc ratio approximately 20-fold, while transferrin receptor expression decreased approx. 10-fold. Level of ATP was similar across all cell types and culture conditions. These results highlight the potential of magnetotactic bacterial gene expression for improving MR contrast.http://journal.frontiersin.org/Journal/10.3389/fmicb.2014.00029/fullIronMagnetic Resonance ImagingCancer cellsMagAmodified ferritin subunitsrelaxation rates |
| spellingShingle | Anindita eSengupta Anindita eSengupta Anindita eSengupta Karina eQuiaoit Karina eQuiaoit Karina eQuiaoit R Terry Thompson R Terry Thompson Frank S Prato Frank S Prato Neil eGelman Neil eGelman Donna E Goldhawk Donna E Goldhawk Donna E Goldhawk Biophysical features of MagA expression in mammalian cells: implications for MRI contrast Frontiers in Microbiology Iron Magnetic Resonance Imaging Cancer cells MagA modified ferritin subunits relaxation rates |
| title | Biophysical features of MagA expression in mammalian cells: implications for MRI contrast |
| title_full | Biophysical features of MagA expression in mammalian cells: implications for MRI contrast |
| title_fullStr | Biophysical features of MagA expression in mammalian cells: implications for MRI contrast |
| title_full_unstemmed | Biophysical features of MagA expression in mammalian cells: implications for MRI contrast |
| title_short | Biophysical features of MagA expression in mammalian cells: implications for MRI contrast |
| title_sort | biophysical features of maga expression in mammalian cells implications for mri contrast |
| topic | Iron Magnetic Resonance Imaging Cancer cells MagA modified ferritin subunits relaxation rates |
| url | http://journal.frontiersin.org/Journal/10.3389/fmicb.2014.00029/full |
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