Numerical investigation of the active role of the actin cytoskeleton in the compression resistance of cells

A thermodynamically motivated model for stress-fiber reorganization

“…; (ii) the remodeling rate constant that depends on whether the cell is for example a progenitor cell compared to a differentiated cell and (iii) the passive elastic properties. In this study, where possible, we attempt to use parameters calibrated for epithelial cells from the studies of McGarry et al (2009) and Ronan et al (2012) and emphasize that we anticipate only 0 , and the passive elastic properties to change significantly with cell type. The passive elastic parameters are taken to be = 5.0 kPa and = 0.45, while the maximum contractile stress max = 240 kPa consistent with a wide range of measurements on muscle fibers (Lucas et al 1995).…”

Cellular contractility and substrate elasticity: a numerical investigation of the actin cytoskeleton and cell adhesion

“…It is not correct to restrict SF orientations to the axisymmetric plane. As previously described by Ronan et al, (2012), the material model is implemented in a 3D framework ( Figure 1). The active stress is calculated by summing the contributions of each fibre.…”

“…This expanded model is implemented in a mixed mode formulation that allows for both normal and tangential stretching of FA bonds between the cell and substrate. This mixed mode interface formulation is employed with the 3D SF implementation of Ronan et al to examine the effect of substrate stiffness on SF and FA formation (Deshpande et al 2007(Deshpande et al , 2006Ronan et al 2012). The current study builds upon previous applications of the SF framework (Pathak et al 2012;McGarry et al 2009;Ronan et al 2012); previous studies have not considered mixed mode FA behaviour, passive/non-specific adhesion forces, cell spreading, or cells adhered to elastic substrates in a 3D environment.…”

Computational investigation of in situ chondrocyte deformation and actin cytoskeleton remodelling under physiological loading

“…Full details of the 3D active stress fibre framework can be found in Deshpande et al [26] and Ronan et al [27]. In summary, a kinetic equation describes the formation and dissociation of the actin cytoskeleton:…”

“…The active formulation is implemented into a 3D framework [27], and the model is implemented in the finite element software Abaqus 6.10 (Simulia, Providence, RI, USA) via a user-defined material subroutine (UMAT) [23]. At every integration point, the theoretical framework is solved in 240 evenly spaced directions in 3D space, providing a full prediction of the distribution of the inhomogeneous anisotropic contractile actin cytoskeleton [27].…”