Osmotic gradient induces stable dome morphogenesis on extracellular matrix.

One of the fundamental processes in morphogenesis is dome formation, but many of the mechanisms involved are unexplored. Previous in vitro studies showed that an osmotic gradient is the driving factor of dome formation. However, these investigations were performed without extracellular matrix (ECM), which provides structural support to morphogenesis. With the use of ECM, we observed that basal hypertonic stress induced stable domes in vitro that have not been seen in previous studies. These domes developed as a result of ECM swelling via aquaporin water transport activity. Based on computer simulation, uneven swelling, with a positive feedback between cell stretching and enhanced water transport, was a cause of dome formation. These results indicate that osmotic gradients induce dome morphogenesis via both enhanced water transport activity and subsequent ECM swelling.