Bioelectric control of tissue mechanics: Effect of membrane potential on somite deformability in chick embryos

Somite segmentation is a crucial process during early embryogenesis, where the timing of somite emergence and somite growth have to be precisely coordinated. Our recent findings established membrane potential (V_m) as a key factor that synchronously controls the rate of somite formation and growth. However, the mechanism through which V_m regulates somitogenesis remains elusive. In this study, using chick embryos, we show that changes in V_m are associated with alterations in the stiffness of somite-forming cells, both in the natural course of development and in response to introduced modifications. As they develop, somites become progressively hyperpolarized and stiffer. Apart from these changes with maturation, chemical microenvironment inducive for depolarization, softens somite-forming cells, while the one causing hyperpolarization increases their stiffness. This response of biomechanical properties to V_m alterations is independent of the somite developmental advancement. Our results show a linear correlation between changes in somite deformability and induced V_m variations, suggesting that previously observed V_m-dependent alterations in the rate of somitogenesis may be linked to changes in cell stiffness. These findings identify cell mechanics as an important factor through which V_m can affect processes underlying somitogenesis progression by translating external chemical signals to intracellular mechanical cues.