Scanning electrochemical microscopy for the stimulation and investigation of human skeletal muscle-derived mesenchymal stem/stromal cells

Introduction: The human skeletal muscle-derived mesenchymal stem/stromal cells (SM-MSCs) possess myogenic differentiation potential and participate in the muscle regeneration process. However, the question of how to improve human skeletal muscle regeneration remains actual. In this study, the total SM-MSCs population was separated into subpopulations according to the neural cell adhesion molecule (NCAM, CD56), stimulated with an alternating electric field (AC) using scanning electrochemical microscopy (AC-SECM) and the intracellular redox changes, and myogenic differentiation markers were evaluated. Methods: The total SM-MSC population was isolated from the postoperative human skeletal muscle biopsies by an enzymatic digestion method. The myogenic differentiation of the total SM-MSCs population before and after AC stimulation was evaluated immunohistochemically by the levels of desmin and myogenin. The effect of AC stimulation on the redox capacity of CD56(+) and CD56(-) cell subpopulations as well as on the level of myogenin on indium tin oxide (ITO) surface were also investigated. Results: The total SM-MSCs population grown on a glass coverslip weakly responded to AC stimulus, i.e. the level of desmin was slightly increased by the 3rd day of differentiation, while in the not stimulated cells, it increased only by the 7th day. The level of myogenin did not change after AC stimulation. However, the CD56(+) and CD56(-) subpopulations had different redox activities and myogenic differentiation potential: the CD56(+) cells had stronger natural diffusion and were more redox active compared to the CD56(-) cells; the redox activity of CD56(+) cells was more actively stimulated by an alternating electric field than in CD56(-) cells; at control level, the CD56(+) cells had more myogenic differentiation-regulating transcription factor myogenin, which was more intensively stimulated by AC than in CD56(-) cells. Data show that the total population of human SM-MSCs is heterogeneous with different regenerating potential cells that do not equally respond to extracellular stimuli. The SECM can be used in both ways: (i) for extracellular stimulation and (ii) for the investigation of intracellular redox changes of the human SM-MSCs or their subpopulations allowing a deeper understanding of the mechanisms mediating skeletal tissue regeneration both in vitro and in vivo.

Automated summary

This study separated the total population of human skeletal muscle-derived mesenchymal stem/stromal cells (SM-MSCs) into different subpopulations using scanning electrochemical microscopy (AC-SECM) and evaluated their redox changes and myogenic differentiation potential. The results showed that the CD56(+) and CD56(-) subpopulations had different redox activities and myogenic differentiation potential, indicating that the total population of human SM-MSCs is heterogeneous and unevenly responsive to extracellular stimuli.