Computational studies on strain transmission from a collagen gel construct to a cell and its internal cytoskeletal filaments

We developed a mechanical tissue model containing a cell with cytoskeletal filaments inside to investigate how tissue deformation is reflected in the deformation of a cell and its internal cytoskeletal filaments. Tissue that assumes a collagen gel construct was depicted as an isotropic linear elastic material, and the cell was modeled as an assembly of discrete elements including a cell membrane, nuclear envelope, and cytoskeletal filaments. Mechanical behaviors were calculated based on the minimum energy principle. The results demonstrated the effects of the type of tissue deformation on deformations of cytoskeletal filaments. The distribution of strains of cytoskeletal filaments was skewed toward compression when a tissue was stretched, toward stretch when the tissue was compressed, and almost normal when the tissue was sheared. The results also addressed the dependency of deformations of a cell and cytoskeletal filaments on the ratio of the Young’s modulus of a tissue to that of a cell. Upon tissue stretching, cell strain increased and the distribution of strains of cytoskeletal filaments broadened on both stretch and compression sides with an increase in the Young’s modulus ratio. This suggested that the manner of tissue deformation and the tissue/cell Young’s modulus ratio are reflected in the distribution pattern of strains of cytoskeletal filaments. The present model is valuable to understanding the mechanisms of cellular responses in a tissue.