Nonlinear Elasticity of Biological Fibrous Networks Facilitates Efficient Inter-cellular Mechaical Signalling

Cells embedded in fibrous matrices form inter-cellular bands of dense and aligned fibres, through which they mechanically interact. This study was aimed at exploring the effects of elastic nonlinearity of the fibres contained in the ECM, on the transmission of mechanical loads between contracting cells. We developed a finite-element model of two cells embedded within a fibrous network. The individual fibres were modelled as showing linear elasticity, compression-microbuckling and/or tension-stiffening. Buckling resulted in the distributions of loads showing greater concentration in the inter-cellular region of the matrix and being more directed towards the neighbouring cell; tension-stiffening further contributed to this, though to a smaller extent. Nonlinear elasticity contributed also to the onset of force polarity on the cell edges, manifested in larger contractile forces on the part of the cell pointing towards the neighbouring cell. The density and alignment of the fibres within the inter-cellular band were considerably greater when fibres were bucklable, with tension-stiffening further contributing to this. The model demonstrates the contribution of nonlinear elasticity of biological gels to the efficient mechanical-signal transfer between distant cells.