Mechanical regulation of water permeability in cells: a modelling study

CECCARELLI, ALBERTO; OZU, MARCELO; CHARA, OSVALDO

Buenos Aires

Congreso; Latin American Conference on Mathematical Modeling of Biological Systems - Encuentros, desencuentros y reencuentros entre la matemática aplicada y la biofísica experimental; 2015

Sociedad Argentina de Biofísica

Osmotically-induced water transport across plasma membrane fullydetermines cell volume at times in the order of seconds to minutes. Thistransport is mainly controlled by proteins working as water channels knownas aquaporins (AQPs). The presence of these channels is functionallyevidenced by measurements of water permeability. Based on experimentalevidences it was recently proposed1 that AQPs could be mechanicallyregulated although the precise mechanism of this regulation is stillunknown. In this project, we propose a possible mechanism of suchmechanical regulation that we implemented in a mathematical model of cellvolume dynamics under external osmolarity changes. The model is given bya non-linear ordinary differential equation (ODE) which was convenientlynondimensionalized to reduce the number of model parameters. The modelwas constrained by using experimental information from typical osmoticswelling assays. Fitting the model to experimental kinetics of swelling ofXenopus laevis oocytes under hyposmotic conditions determined byvideomicroscopy indicates that the mechanism is sufficient to explain theobserved phenomenology.