Characterization of mesenchymal stem cells with augmented internalization of magnetic nanoparticles: The implication of therapeutic potential

Mesenchymal stem cells (MSCs) possess the potential to repair damaged tissue and regenerate the cells with a specific function. MSCs dispersed in the circulatory system tend to enter pulmonary tissue, arming the ability to change the lung microenvironment, prevent pulmonary fibrosis, and treat pulmonary injuries. It has been demonstrated that magnetic nanoparticles (MNPs) not only can be used as the vector for drug delivery, which can improve the specificity and control the drug released; but also act as the contract media for imaging, possessing the potential of being tracer and conducting differentiation to comply repairment. Epigallocatechin gallate (EGCG) has been known to greatly enhance MNP uptake by tumor cells under the influence of magnetic fields. However, whether EGCG significantly improves the MNP uptake by MSCs in the magnetic fields and whether MSCs maintain the characteristics of MSCs with such treatment remains unknown. In this study, we demonstrated that EGCG significantly enhanced the MNP uptake by MSCs in the magnetic field. With 30 µM EGCG in the magnetic field for 2 h, the cell-associated MNPs are increased 7.1 and 3.4 times by mouse and human MSCs without a distinguished influence on cell morphology, respectively. Furthermore, we evaluated the osteogenic differentiation potential of human MSCs after MNP uptake by assessing the relative gene expressions of osteogenic markers Runt-related transcription factor 2 (RUNX2), Osterix (Sp7), and Alkaline phosphatase (ALPL). There is no definite evidence showing that the expressions of these osteogenic marker genes, upon MNPs uptake, are significantly different from those of the control group. Surface antigen expression assay by flow cytometry revealed a similar expression population of human MSC surface markers CD73 and CD90. The results suggest that the stemness and differentiation capacity of MSCs are not affected after the MNP uptake. Our study demonstrates that combining EGCG and magnetic fields is an effective method to enhance MNP uptake by MSCs. The study serves as the foundation of the research related to the clinical application of combining MNPs and MSCs. We anticipate that the therapeutic potential of MSCs can be explored further to treat new coronary pneumonia and other diseases through this research platform.