Mechanical regulation of water permeability in cells: a modelling study

CECCARELLI, ALBERTO; OZU MARCELO; CHARA OSVALDO

Buenos Aires

Conferencia; Latin American Conference on Mathematical Modelling of Biological Systems; 2015

Sociedad Argentina de Biofisica (SAB)

Osmotically-induced water transport across plasma membrane fullydetermines cell volume at times in the order of seconds to minutes. This transport is mainly controlled by proteins working as water channels known as aquaporins (AQPs). The presence of these channels is functionally evidenced by measurements of water permeability. Based on experimental evidences it was recently proposed1 that AQPs could be mechanically regulated although the precise mechanism of this regulation is still unknown. In this project, we propose a possible mechanism of such mechanical regulation that we implemented in a mathematical model of cell volume dynamics under external osmolarity changes. The model is given by a non-linear ordinary differential equation (ODE) which was conveniently nondimensionalized to reduce the number of model parameters. The model was constrained by using experimental information from typical osmotic swelling assays. Fitting the model to experimental kinetics of swelling of Xenopus laevis oocytes under hyposmotic conditions determined by videomicroscopy indicates that the mechanism is sufficient to explain the observed phenomenology.[1] Ozu et al., 2013. Biophys J. 104(1): 85-95.