Viscoelasticity and cell swirling motion

Abstract

Although collective cell migration (CCM) is a highly coordinated and fine-tuned migratory mode, instabilities in the form of cell swirling motion (CSM) often occur. The CSM represents a product of the active turbulence obtained at low Reynolds number which has a feedback impact on various processes such as: morphogenesis, wound healing, and cancer invasion. The cause of this phenomenon is related to the viscoelasticity of multicellular systems in the context of cell residual stress accumulation. Particular interest of this work is to: (1) consider the tissue cohesiveness as the main parameter responsible for the CSM appearance, (2) discuss the viscoelasticity of multicellular systems caused by CCM by clarifying the roles of cell shear and normal residual stresses, and (3) describe the dynamics of CSM in the context of mechanical waves generation based on multiscale modeling consideration. While the cell normal residual stress induces an increase in cell packing density capable of reducing the tissue cohesiveness of healthy epithelium, the shear residual stress exerts work via shear stress torque against the tissue surface tension and can induce the CSM. Inhomogeneous distribution of the cell residual stress within the swirl leads to the generation of viscoelastic force capable of suppressing the CCM. This force together with the surface tension force acts against the centrifugal force and induces the swirl radial pulsations connected with successive stiffening and softening. In this work, a review of existing literature about viscoelasticity caused by CCM is given along with assortment of published experimental findings, in order to invite experimentalists to test given theoretical considerations in multicellular systems.