Viscoelasticity of multicellular systems caused by collective cell migration: dynamics at the biointerface

2020

Front. Phys.

Self Cite

Various types of mechanical waves, such as propagative waves and standing waves, are observed during 2D collective cell migration. Propagative waves are generated during monolayer free expansion, whereas standing waves are generated during swirling motion of a confluent monolayer. Significant attempts have been made to describe the main characteristics of mechanical waves obtained within various experimental systems. However, much less attention is paid to correlate the viscoelasticity with the generated oscillatory instabilities. Mechanical waves have recognized during flow of various viscoelastic systems under low Reynolds number and called "the elastic turbulence." In addition to Reynolds number, Weissenberg number is needed for characterizing the elastic turbulence. The viscoelastic resistive force generated during collective cell migration caused by a residual stress accumulation is capable of inducing apparent inertial effects by balancing with other forces such as the surface tension force, the traction force, and the resultant force responsible for cell migration. The resultant force represents a product of various biochemical processes such as cell signaling and gene expression. The force balance induces (1) forward flow and backward flow in the direction of cell migration as characteristics of the propagative waves and (2) inflow and outflow perpendicular to the direction of migration as characteristics of the standing waves. The apparent inertial effects are essential for appearing the elastic turbulence and represent the characteristic of (1) the backward flow during the monolayer free expansion and (2) the inflow during the cell swirling motion within a confluent monolayer.

Section: Viscoelasticity Of Multicellular Systemsmentioning

confidence: 99%

Section: Viscoelasticity Of Multicellular Systemsmentioning

confidence: 99%

Mechanical Oscillations in 2D Collective Cell Migration: The Elastic Turbulence

2020

Front. Phys.

Self Cite

“…Cells in the passive state are placed in the internal region, while the active cells are placed in the boundary regions of the collision zone. Consequently, the viscoelasticity of the CZ depends on (1) the volume fraction of migrating cells, ϕ m , (2) the volume fraction of passive (resting) cells ϕ r such that ϕ r = 1 − ϕ m , (3) the viscoelasticity of migrating cells (where is the shear or normal stress generated within a migrating cell pseudo phase and is the corresponding shear and volumetric strain), and (4) the viscoelasticity of passive (resting) cells (where is the shear or normal stress generated within a resting cell pseudo-phase and is the corresponding shear and volumetric strain), (Pajic-Lijakovic and Milivojevic, 2019a;2020a). This “sandwich structure” of cell-pseudo-phases pointed to parallel mode coupling described by Pajic-Lijakovic and Milivojevic (2019a;2020a).…”

Section: The Viscoelasticity Regimes and The Stiffness Of The Collision Zonementioning

confidence: 99%

“…This contribution represents an attempt to clarify this issue. This pseudo-phase transition influence the mechanical state of single cells (Pajic-Lijakovic and Milivojevic, 2019a;2020a,b). Zimmermann et al (2016) considered the cell jamming state transition during CCM of MDCK cell monolayers and revealed that cells under jamming state actively down-regulate their propulsion forces in response to an increase in cell packing density by discussing the contact inhibition of locomotion (CIL) as the main mechanisms.…”

Section: Introductionmentioning

confidence: 99%

The role of viscoelasticity in long-time cell rearrangement

2021

Preprint

Self Cite

Although collective cell migration (CCM) is a highly coordinated and ordered migratory mode, perturbations in the form of mechanical waves appear even in 2D. These perturbations caused by the viscoelastic nature of cell rearrangement are involved in various biological processes, such as embryogenesis, wound healing and cancer invasion. The mechanical waves, as a product of the active turbulence occurred at low Reynolds number, represent an oscillatory change in cell velocity and the relevant rheological parameters. The velocity oscillations, in the form of forward and backward flows, are driven by: viscoelastic force, surface tension force, and traction force. The viscoelastic force represents a consequence of inhomogeneous distribution of cell residual stress accumulated during CCM. This cause-consequence relation is considered on a model system such as the cell monolayer free expansion. The collision of forward and backward flows causes an increase in cell packing density which has a feedback impact on the tissue viscoelasticity and on that base influences the tissue stiffness. The evidence of how the tissue stiffness is changed near the cell jamming is conflicting. To fill this gap, we discussed the density driven change in the tissue viscoelasticity by accounting for the cell pseudo-phase transition from active (contractile) to passive (non-contractile) state appeared near cell jamming in the rheological modeling consideration.

“…Every viscoelastic state per regime should be characterized by appropriate stress-strain constitutive model. Milivojevic (2019aMilivojevic ( ,2020a reported that CCM induces generation of stress, its relaxation, and the residual stress accumulation. The stress can be normal (compressive and tensile) and shear.…”

mentioning

confidence: 99%

Viscoelasticity and cell jamming state transition

2021

Preprint

Self Cite

Although collective cell migration (CCM) is a highly coordinated migratory mode, perturbations in the form of jamming state transitions and vice versa often occur even in 2D. These perturbations are involved in various biological processes, such as embryogenesis, wound healing and cancer invasion. CCM induces accumulation of cell residual stress which has a feedback impact to cell packing density. Density-mediated change of cell mobility influences the state of viscoelasticity of multicellular systems and on that base the jamming state transition. Although a good comprehension of how cells collectively migrate by following molecular rules has been generated, the impact of cellular rearrangements on cell viscoelasticity remains less understood. Thus, considering the density driven evolution of viscoelasticity caused by reduction of cell mobility could result in a powerful tool in order to address the contribution of cell jamming state transition in CCM and help to understand this important but still controversial topic. In addition, five viscoelastic states gained within three regimes: (1) convective regime, (2) conductive regime, and (3) damped-conductive regime was discussed based on the modeling consideration with special emphasis of jamming and unjamming states.