[Effect of the tissue architecture on cell-to-cell calcium signaling]

A novel approach based on the approximation of tissue structure by the Voronoi diagram has been elaborated to study cell-to-cell signaling in a tissue mediated by gap junctions. This methodology was applied for the analysis of Ca2+ signaling in the airway epithelium, where adjacent cells were taken to be coupled by gap junctions whose permeability depended on Ca2+ concentration in their cytoplasm. The number of junctional channels connecting a given pair of cells was postulated to be directly proportional to the length of the boundary between them. In a certain range of parameters, a modeled cell generate intracellular Ca2+ oscillations upon the stimulation with the purinergic agonist ATP, and the Ca2+ signal propagated through the tissue due to a Ca2+ rise in adjacent connected cells. The influence of variable sensitivity of cells to ATP on Ca2+ signaling in the tissue was also examined. The model also showed that a mechanical disturbance of a single airway epithelial cell resulted in a prolonged increase in Ca2+ concentration in its cytoplasm, which entailed the spreading of a Ca2+ wave along the tissue.