Membrane tension regulated mechanotransduction drives fate transitions in embryonic stem cells

Changes in cell shape and mechanics frequently accompany cell fate transitions. Yet how cellular mechanics affects the regulatory pathways controlling cell fate is poorly understood. To probe the interplay between shape, mechanics and fate, we used embryonic stem (ES) cells, which spread as they undergo early differentiation. We found that this spreading is regulated by a β-catenin mediated decrease in RhoA activity and subsequent decrease in the plasma membrane tension. Strikingly, preventing the membrane tension decrease resulted in early differentiation defects in ES cells and gastruloids. We further find that the decrease in membrane tension facilitates endocytosis of FGF signaling components, which activates ERK signaling and directs exit from the ES cell state. The early differentiation defects we observed can be rescued by increasing Rab5afacilitated endocytosis. Thus, we show that a mechanically-triggered increase in endocytosis regulates early differentiation. Our findings are of fundamental importance for understanding how cell mechanics regulates biochemical signaling, and therefore cell fate. mESC from parental cell line E14 wt and from inducible constitutively active Ezrin (iEZR_CA) were seeded on gelatin-coated plates in 2i+LIF (naive medium) or N2B27 (differentiation medium). The expression of Ezrin was induced ~16hr before exit by the addition of doxycycline to the medium. RNA lysates were collected at 24hr and 48hr of exit from the naive and differentiated cells in both cell lines. 3 replicates per condition were processed.