Temporal instability of the frontier between mechanically regulated tissues

Abstract: The stability of the boundary between regenerating tissues is essential to the maintenance of their integrity and biological function. Stress is known to play an important role in the regulation of cell division, cell growth and cell death, and it is thought that stress balance ensures the stability of tissue boundaries. Using a multicellular numerical model, we investigate the stability of the frontier between two confluent cell monolayers whose cell renewal is mechanically regulated. We show that even for two tissues having similar mechanical and biological properties, the location of their common frontier is subject to strong fluctuations until the complete disappearance of one of the tissues. Using a population dynamics model, we show that this temporal instability is inherent to the stochasticity of cell division and cell death events, and derive an analytical expression for the mean disappearance time of a tissue. These results call for a rethinking of the regulating mechanism of tissue renewal.