Topographical evaluation of human mesenchymal stem cells during osteogenic differentiation using scanning ion conductance microscopy

Abstract

Human mesenchymal stem cells (hMSCs) have attracted considerable attention as valuable cell sources for regenerative medicine in various diseases. Osteogenic differentiation is one of the capabilities of hMSCs that is critical to their clinical applications. Morphological measurements are essential for monitoring hMSC osteogenic differentiation because they are non-destructive and conserve valuable cell sources. However, the three-dimensional topography of cells during differentiation has not been fully investigated. Here, we quantified the time-course changes in hMSC topography during osteogenic differentiation using scanning ion conductance microscopy (SICM). Rapidly expanding clone (REC), an hMSC subpopulation with high proliferation and differentiation potencies, and conventional hMSCs (cMSCs) were used as the hMSC sources. In the osteogenic differentiation medium, RECs and cMSCs showed lower cell heights than those in the undifferentiation medium, indicating the occurrence of morphological changes during the osteogenic differentiation. Interestingly, during differentiation, RECs exhibited a low height at the beginning of the culture period (day 1), while the height of cMSCs gradually decreased, implying that RECs had a higher differentiation capacity than cMSCs. The three-dimensional topographical information will contribute to a deeper understanding of hMSC osteogenic differentiation and may become an important differentiation indicator in future clinical applications.