Radioisotope imaging of microRNA-9-regulating neurogenesis using sodium iodide sympoter

Since microRNAs (miRNA, miR) are known to be critical in various cellular processes and diseases, non-invasive molecular imaging system for miRNA is very important for imaging cellular therapy and disease diagnosis. In this study, we developed a radionuclide imaging system for miR-9 using sodium iodide symporter (NIS). During neuronal differentiation of P 19 cells induced by the treatment of retinoic acid (RA), in vitro and in vivo imaging demonstrated that the expression and activity of NIS from the miR-9 NIS reporter gene was clearly repressed by the increased expression and functional activity of miR-9 that bound with the target sequences in the NIS reporter gene and resulted in destabilized the transcriptional activity of NIS gene, compared with the undifferentiated P19 cells. The decreased activity of NIS from the differentiated P19 cells resulted in low uptake of radionuclide and decreased radioisotope signals. The NIS reporter gene-based miRNA imaging system showed a great specificity of imaging miRNA biogenesis during cellular developments. The miRNA NIS reporter gene will provide high sensitive imaging for visualizing miRNA-regulating cellular developments and diseases.