Efficient and Rapid Labeling of Transplanted Cell Populations with Superparamagnetic Iron Oxide Nanoparticles Using Cell Surface Chemical Biotinylation for in Vivo Monitoring by MRI

Abstract

Determination of the dynamics of specific cell populations in vivo is essential for the development of cellbased therapies. For cell tracking by magnetic resonance imaging (MRI), cells need to internalize, or be surface labeled with a MRI contrast agent, such as superparamagnetic iron oxide nanoparticles (SPIOs): SPIOs give rise to signal loss by gradient-echo and T 2 -weighted MRI techniques. In this study, cancer cells were chemically tagged with biotin and then magnetically labeled with anti-biotin SPIOs. No significant detrimental effects on cell viability or death were observed following cell biotinylation. SPIO-labeled cells exhibited signal loss compared to non-SPIO-labeled cells by MRI in vitro. Consistent with the in vitro MRI data, signal attenuation was observed in vivo from SPIO-labeled cells injected into the muscle of the hind legs, or implanted subcutaneously into the flanks of mice, correlating with iron detection by histochemical and X-ray fluorescence (XRF) methods. To further validate this approach, human mesenchymal stem cells (hMSCs) were also employed. Chemical biotinylation and SPIO labeling of hMSCs were confirmed by fluorescence microscopy and flow cytometry. The procedure did not affect proliferation and multipotentiality, or lead to increased cell death. The SPIO-labeled hMSCs were shown to exhibit MRI signal reduction in vitro and was detectable in an in vivo model. In this study, we demonstrate a rapid, robust, and generic methodology that may be a useful and practical adjuvant to existing methods of cell labeling for in vivo monitoring by MRI. Further, we have shown the first application of XRF to provide iron maps to validate MRI data in SPIO-labeled cell tracking studies.Key words: Magnetic resonance imaging (MRI); Cell labeling; Chemical biotinylation; Superparamagnetic iron oxide nanoparticles (SPIOs) INTRODUCTIONtracking in vivo [reviewed in (6,22)]. Contrast agents include those based on superparamagnetic iron oxide nanoparticles (SPIOs), which predominantly enhance T 2 The monitoring of specific cell populations is essential for understanding their role in health and disease, relaxation and range from micron size to nanometer size. Labeling of cells for MRI monitoring usually involves and also for the development of cell-based therapies (11,28,36,42). Until relatively recently, tracking particuinternalization of contrast agents, with or without assistance from, for example, polycationic compounds or lar cell populations in vivo has not been possible, such information being derived only from ex vivo histology.translocating peptides (20,33). Alternatively, cells have been tracked in vivo by surface labeling of cells using Magnetic resonance imaging (MRI) is a commonly employed noninvasive imaging modality and cells have cell-specific antibodies that are also conjugated to contrast agents (1 Chemical biotinylation of cells involve reaction of line) were cultured in Dulbecco's modified Eagle's medium (DMEM, Sigma-Aldrich Co. Ltd., Poole, UK) supthe N-hydroxysuccinimide (NHS) este...

Labeling of cynomolgus monkey bone marrow-derived mesenchymal stem cells for cell tracking by multimodality imaging

“…These results indicate that MIRB is biocompatible, and can be used for cell labeling and tracking for cell transplantation. With technological progress in nanotechnology, magnetic nanoparticles can be nontoxic, biocompatible and efficient for intracellular labeling [36,37] such as Feridex, an FDA approved contrast agent for MRI of adult patients to enhance the T2 weighted images used to detect and evaluate liver lesions [38]. However, limited MRI sensitivity cannot distinguish regenerative and differentiated cells from exogenous and endogenous transplanted cells.…”

Clinical imaging in regenerative medicine

“…Biotinylated peptides expressed on the plasma membrane were imaged with a contrast agent conjugated to streptavidin in rodent models 63, 64 . The human membrane-protein sodium-iodide symporter (NIS), responsible for iodide uptake in the thyroid, stomach, salivary gland and choroid plexus but minimally expressed elsewhere, was used to follow the survival and distribution of transplanted cells in pigs by hybrid SPECT/CT 32 .…”

Molecular Imaging of Stem Cells: Tracking Survival, Biodistribution, Tumorigenicity, and Immunogenicity

“…One method, magnetoporation, involves the coating of anionic SPIOs with cationic transfection agents such as protamine sulfate or poly-L-lysine 14. Stem cells subsequently endocytose the resulting complex during incubation for around 24-48 hours 15. Although many studies have shown that magnetoporation does not affect cell viability or function at low doses 15-17, there is evidence that high doses can inhibit mesenchymal stem cell (MSC) migration and colony formation ability 18.…”

“…Stem cells subsequently endocytose the resulting complex during incubation for around 24-48 hours 15. Although many studies have shown that magnetoporation does not affect cell viability or function at low doses 15-17, there is evidence that high doses can inhibit mesenchymal stem cell (MSC) migration and colony formation ability 18. Another study showed inhibition of chondrogenesis in MSCs after FDA-approved Feridex labeling 19.…”