Optimization of Multimodal Imaging of Mesenchymal Stem Cells Using the Human Sodium Iodide Symporter for PET and Cerenkov Luminescence Imaging

Abstract

PurposeThe use of stably integrated reporter gene imaging provides a manner to monitor the in vivo fate of engrafted cells over time in a non-invasive manner. Here, we optimized multimodal imaging (small-animal PET, Cerenkov luminescence imaging (CLI) and bioluminescence imaging (BLI)) of mesenchymal stem cells (MSCs), by means of the human sodium iodide symporter (hNIS) and firefly luciferase (Fluc) as reporters.MethodsFirst, two multicistronic lentiviral vectors (LV) were generated for multimodal imaging: BLI, 124I PET/SPECT and CLI. Expression of the imaging reporter genes was validated in vitro using 99mTcO4 − radioligand uptake experiments and BLI. Uptake kinetics, specificity and tracer elution were determined as well as the effect of the transduction process on the cell's differentiation capacity. MSCs expressing the LV were injected intravenously or subcutaneously and imaged using small-animal PET, CLI and BLI.ResultsThe expression of both imaging reporter genes was functional and specific. An elution of 99mTcO4 − from the cells was observed, with 31% retention after 3 h. After labeling cells with 124I in vitro, a significantly higher CLI signal was noted in hNIS expressing murine MSCs. Furthermore, it was possible to visualize cells injected intravenously using BLI or subcutaneously in mice, using 124I small-animal PET, CLI and BLI.ConclusionsThis study identifies hNIS as a suitable reporter gene for molecular imaging with PET and CLI, as confirmed with BLI through the expression of Fluc. It supports the potential for a wider application of hNIS reporter gene imaging and future clinical applications.

Multipotent adult progenitor cells improve the hematopoietic function in myelodysplasia

“…MAPC cells were transduced with a LV encoding triple flag tagged firefly luciferase (Fluc) and the human sodium iodide symporter (hNIS) further referred to as EF1α-Fluc-hNIS [17]. For selection, 400 ng/mL puromycin (Merck Millipore) was added to the growth medium, and the cells were maintained under these conditions.…”

Lost signature: progress and failures in in vivo tracking of implanted stem cells

“…It was only in 2009 that a sensitive detector was developed, that can measure the low levels of light (consistent with CR) released by positron-emitting radiotracers (Robertson et al 2009). In 2014, CLI was first applied for labeling and detection of stem cells (Wolfs et al 2014). The biggest advantage of the development of this method is the possibility to easily apply established PET tracers.…”

“…Multimodal imaging allows the collection of complementary information from a single experiment. Therefore, it permits taking advantage of a technique's specific strengths, avoiding individual disadvantages, and thus improving single monitoring techniques (De Vocht et al 2012;Srinivas et al 2013;Tang et al 2015;Wolfs et al 2014). BLI, PET, and SPECT show higher sensitivities but lower resolutions than MRI.…”

Cell Tracking Technologies for Acute Ischemic Brain Injury

“…Overlaying simultaneously acquired PET and CT scans therefore enables the integration of structural and functional information, clarifying results, and reducing the likelihood of misinterpretation of data or misdiagnosis in the clinic. More recently, studies exploit the advantages of other techniques, combining MRI with SPECT imaging 92 and PET with bioluminescence, 93 among other examples. The huge advantage of these combinatorial approaches is rapidly becoming apparent to institutions, which are investing in imaging equipment with the capacity to execute more than one imaging modality simultaneously.…”