2D-to-spheroid transition rewires BK channels to regulate endometrial stem/stromal cell migration during spheroid reactivation.

The regulation of multiple biological reactions in stem cells is linked with the functions of different ion channels, and their modulation is considered as an effective approach to control stem cell behavior. Human endometrial-derived mesenchymal stem/stromal cells (eMSCs) are promising candidates for the use in regenerative medicine due to high availability and minimal ethical issues. The cultivation of eMSCs as 3D spheroids was shown to improve its properties for stem cell therapies. Dramatic changes in cell organization occur during 2D-to-spheroid transition, and this potentially affects eMSC signaling pathways including ion channel-dependent reactions. Previously we have identified BK potassium channels in the 2D culture of eMSCs but their impact to cellular reactions remain unidentified. Here, we aimed to determine and compare the role of BK channel activity in the control of 2D eMSC migration and 3D spheroid reactivation. We observed significant decrease of eMSC spheroid spreading rates in the presence of specific BK channel blockers while no effect of BK inhibitors on 2D eMSC migration was detected. Our results show the 2D-to-3D transition resulted in the inclusion of BK channels to the pathways controlling eMSC migration during spheroid reactivation. Our data demonstrates the particular importance to identify the similarities and differences between key ion channel-controlled signaling pathways and physiological reactions in 2D and 3D cell cultures.