Induced pluripotent stem cells (iPSC) derived from somatic cells can be differentiated into various cell lineages. They are valuable tools in basic cell and developmental biology research and as a potential source of regenerative cells for clinical applications. However, numerous challenges remain in the field of iPSC research, including the need for methods that allow longitudinal noninvasive in vivo monitoring of transplanted cells in multiple animal species and in humans. The reporter gene used for this type of cell marking should encode a protein that is 1) non-immunogenic, 2) can be monitored by noninvasive imaging using clinically approved radiotracers that are readily available, 3) can be used in small and large animal models, and 4) does not interfere with cellular function. NIS, the thyroidal sodium iodide symporter, is an ideal reporter gene for cell tracking applications. NIS is endogenously expressed in thyroid follicular cells where its role is to concentrate iodine for the synthesis of thyroid hormones6. For more than 70 years, thyroidal NIS expression has been clinically exploited, providing the basis for 123I gamma camera or SPECT/CT imaging in thyroid disorders and for 131I tumor ablation of metastatic thyroid cancer. Imanis Life Sciences was founded in 2012 to accelerate research in regenerative medicine by providing a comprehensive set of reagents and imaging services to facilitate NIS reporter gene labeling and noninvasive monitoring of cellular therapies. The overall goal of this grant is to develop NIS-expressing stem cells and iPSC whose differentiated progeny can be serially imaged noninvasively in small and large animal models. During the Phase I period, we will introduce the NIS gene into either of two genomic safe harbors (AAVS1 and ROSA26) of a human iPSC line, with NIS gene expression controlled by EF1a or CAG promoters. The iPSC will be differentiated into cells of the three germ layers, cardiomyocytes (mesoderm), insulin-producing beta cells (endoderm), and neuronal cells (ectoderm), and NIS expression will be monitored. We hypothesize that NIS gene expression will be constitutively expressed and will not be silenced in undifferentiated or differentiated progeny, regardless of lineage, thus enabling long term monitoring of the gene marked cells in vivo.
Stem cells capable of differentiating into various tissues for repair and regeneration are being developed in animal models but it is difficult to monitor the fate of these therapeutic cells. We thus need a reliable and quantitative method that allows cell fate monitoring in small and large animal models. In this grant, we will develop the NIS imaging technology as a solution for cell fate monitoring, with the goal of accelerating research and development of these therapies into the clinic. Reagents generated here will also be a valuable resource for the research community in general.
| Lu, Brian; Kurmi, Kiran; Munoz-Gomez, Miguel et al. (2018) Impaired ?-cell glucokinase as an underlying mechanism in diet-induced diabetes. Dis Model Mech 11: |
| El Khatib, Moustafa M; Ohmine, Seiga; Jacobus, Egon J et al. (2016) Tumor-Free Transplantation of Patient-Derived Induced Pluripotent Stem Cell Progeny for Customized Islet Regeneration. Stem Cells Transl Med 5:694-702 |
