Contact-controlled amoeboid motility induces dynamic cell trapping in 3D-microstructured surfaces

Abstract

On flat substrates, several cell types exhibit amoeboid migration, which is characterized by restless stochastic successions of pseudopod protrusions. The orientation and frequency of new membrane protrusions characterize efficient search modes, which can respond to external chemical stimuli as observed during chemotaxis in amoebae. To quantify the influence of mechanical stimuli induced by surface topography on the migration modes of the amoeboid model organism Dictyostelium discoideum, we apply high resolution motion analysis in microfabricated pillar arrays of defined density and geometry. Cell motion is analyzed by a two-state motility-model, distinguishing directed cellular runs from phases of isotropic migration that are characterized by randomly oriented cellular protrusions. Cells lacking myosin II or cells deprived of microtubules show significantly different behavior concerning migration velocities and migrational angle distribution, without pronounced attraction to pillars. We conclude that microtubules enhance cellular ability to react with external 3D structures. Our experiments on wild-type cells show that the switching from randomly formed pseudopods to a stabilized leading pseudopod is triggered by contact with surface structures. These alternating processes guide cells according to the available surface in their 3D environment, which we observed dynamically and in steady-state situations. As a consequence, cells perform ''home-runs'' in low-density pillar arrays, crawling from pillar to pillar, with a characteristic dwell time of $75 s. At the boundary between a flat surface and a 3D structured substrate, cells preferentially localize in contact with micropillars, due to the additionally available surface in the microstructured arrays. Such responses of cell motility to microstructures might open new possibilities for cell sorting in surface structured arrays.

Chemotaxis and topotaxis add vectorially for amoeboid cell migration

“…The height and diameter of the pillars is the same (8 µm) and comparable to the typical size of a D. discoideum cell, which varies between 8-15 µm 40 . This ratio between pillar height and cell size is sufficient to keep the motion of starved D. discoideum two-dimensional, meaning the pillars act as obstacles, as observed in previous studies 38,41 . Cells fully mounting the pillars are rarely observed and excluded from the data.…”

“…These persistent random walks become biased when external guidance cues are present, resulting in an effective drift. Aside from chemical gradients, D. discoideum migration can be influenced topographically 38 . Thus, embedding the amoeba in asymmetric pillar fields, overlaid with a chemical gradient, yields a topo-chemical multi-cue environment capable of studying the significance of topotaxis for highly motile amoeboid movement.…”

Microstructured Blood Vessel Surrogates Reveal Structural Tropism of Motile Malaria Parasites

“…[10] In these arrays, the uniform pillars do not serve as substrates for cell adhesion but as obstacles for the migrating cells, which can be different types of eukaryotic or bacterial cells. [10][11][12][13][14][15] These studies showed that the distance between the pillars affects the migration patterns of cells.…”

Tailored environments to study motile cells and pathogens

“…Furthermore, additional contact sites were provided in the form of pillars to study their effect on the migratory and adhesive behaviour of Dictyostelium discoideum (Arcizet et al, ). Other investigated motile cells include free‐swimming diatoms and dinoflagellates as well as the parasitic protozoans Giardia and Entamoeba (Figure e).…”

“…iour of Dictyostelium discoideum(Arcizet et al, 2012). Other investigated motile cells include free-swimming diatoms and dinoflagellates as well as the parasitic protozoans Giardia and Entamoeba(Figure 4e).…”