Cell Migration with Multiple Pseudopodia: Temporal and Spatial Sensing Models

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Abstract Cell migration triggered by pseudopodia (or "false feet") is the most used method of locomotion. A 3D finite element model of a cell migrating over a 2D substrate is proposed, with a particular focus on the mechanical aspects of the biological phenomenon. The decomposition of the deformation gradient is used to reproduce the cyclic phases of protrusion and contraction of the cell, which are tightly synchronized with the adhesion forces at the back and at the front of the cell, respectively. First, a steady active deformation is considered to show the ability of the cell to simultaneously initiate multiple pseudopodia. Here, randomness is considered as a key aspect, which controls both the direction and the amplitude of the false feet. Second, the migration process is described through two different strategies: the temporal and the spatial sensing models. In the temporal model, the cell "sniffs" the surroundings by extending several pseudopodia and only the one that receives a positive input will become the new leading edge, while the others retract. In the spatial model instead, the cell senses the external sources at different spots of the membrane and only protrudes one pseudopod in the direction of the most attractive one.

A computational mechanics approach to assess the link between cell morphology and forces during confined migration

“…Third, the intra-synchronization is presented. As in our previous works (Allena and Aubry 2012;Allena 2013), this represents the key ingredient of the cell movement. In fact, we show how the cyclic active strains (i.e.…”

“…strains generated by the interaction with the environment) strains undergone by the cell; -contrary to previous works Tozluoglu et al 2013), the cell is modelled as a continuum. Nonetheless, both the cytoplasm and the nucleus have been originally represented through two characteristic functions, and a standard Maxwell model has been used to describe their viscoelastic behaviour (Allena and Aubry 2012;Allena 2013;Tozluoglu et al 2013); -the cell is able to cyclically protrude and contract. Such active strains are triggered respectively by the polymerization and depolymerization of the actin filaments and are synchronized with the viscous adhesion forces between the cell and the substrate (Allena and Aubry 2012; Allena 2013); -the micro-channel is represented by two rigid walls, which are described by two characteristic functions, and exerts an additional normal viscous force on the cell boundaries when contact condition is fulfilled.…”

“…5.1). Additionally, the cell cyclically generates a frontal ( f ) and a rear ( r ) adhesion region in order to move forward (Allena and Aubry 2012;Allena 2013) (Fig. 1b, Sect.…”

“…In our previous works (Allena and Aubry 2012;Allena 2013), we have presented numerical models which helped to understand the mechanisms controlling cell motility on twodimensional (2D) flat surfaces. Nevertheless, during many biological processes such as embryogenesis, immunity and tumorogenesis, cell migration takes place in confined environments of tissues (Friedl and Wolf 2010).…”

“…Such models have used different approaches resulting in force-based dynamics models (Zaman et al 2005(Zaman et al , 2006, stochastic models to simulate persistent random walks (Tranquillo and Lauffenburger 1987;Tranquillo et al 1988;, models reproducing the movement of cancer cell spheroids (McElwain and Ponzo 1977;McElwain 1978;McElwain et al 1979), Monte Carlo models (Zaman et al 2007; or purely mechanical models (Allena and Aubry 2012;Allena 2013). Active gel layers submitted to external forces have been used to represent acto-myosin cells migrating in a free or confined (Hawkins et al 2009;Hawkins and Voituriez 2010) environment.…”