TY - JOUR A1 - Moreno, Eduardo A1 - Großmann, Robert A1 - Beta, Carsten A1 - Alonso, Sergio T1 - From single to collective motion of social amoebae BT - a computational study of interacting cells JF - Frontiers in physics N2 - The coupling of the internal mechanisms of cell polarization to cell shape deformations and subsequent cell crawling poses many interdisciplinary scientific challenges. Several mathematical approaches have been proposed to model the coupling of both processes, where one of the most successful methods relies on a phase field that encodes the morphology of the cell, together with the integration of partial differential equations that account for the polarization mechanism inside the cell domain as defined by the phase field. This approach has been previously employed to model the motion of single cells of the social amoeba Dictyostelium discoideum, a widely used model organism to study actin-driven motility and chemotaxis of eukaryotic cells. Besides single cell motility, Dictyostelium discoideum is also well-known for its collective behavior. Here, we extend the previously introduced model for single cell motility to describe the collective motion of large populations of interacting amoebae by including repulsive interactions between the cells. We performed numerical simulations of this model, first characterizing the motion of single cells in terms of their polarity and velocity vectors. We then systematically studied the collisions between two cells that provided the basic interaction scenarios also observed in larger ensembles of interacting amoebae. Finally, the relevance of the cell density was analyzed, revealing a systematic decrease of the motility with density, associated with the formation of transient cell clusters that emerge in this system even though our model does not include any attractive interactions between cells. This model is a prototypical active matter system for the investigation of the emergent collective dynamics of deformable, self-driven cells with a highly complex, nonlinear coupling of cell shape deformations, self-propulsion and repulsive cell-cell interactions. Understanding these self-organization processes of cells like their autonomous aggregation is of high relevance as collective amoeboid motility is part of wound healing, embryonic morphogenesis or pathological processes like the spreading of metastatic cancer cells. KW - cell motility KW - cell polarity KW - reaction-diffusion models KW - cell-cell KW - interactions KW - phase field model KW - collective motion KW - active matter Y1 - 2022 U6 - https://doi.org/10.3389/fphy.2021.750187 SN - 2296-424X VL - 9 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Moldenhawer, Ted A1 - Moreno, Eduardo A1 - Schindler, Daniel A1 - Flemming, Sven A1 - Holschneider, Matthias A1 - Huisinga, Wilhelm A1 - Alonso, Sergio A1 - Beta, Carsten T1 - Spontaneous transitions between amoeboid and keratocyte-like modes of migration JF - Frontiers in Cell and Developmental Biology N2 - The motility of adherent eukaryotic cells is driven by the dynamics of the actin cytoskeleton. Despite the common force-generating actin machinery, different cell types often show diverse modes of locomotion that differ in their shape dynamics, speed, and persistence of motion. Recently, experiments in Dictyostelium discoideum have revealed that different motility modes can be induced in this model organism, depending on genetic modifications, developmental conditions, and synthetic changes of intracellular signaling. Here, we report experimental evidence that in a mutated D. discoideum cell line with increased Ras activity, switches between two distinct migratory modes, the amoeboid and fan-shaped type of locomotion, can even spontaneously occur within the same cell. We observed and characterized repeated and reversible switchings between the two modes of locomotion, suggesting that they are distinct behavioral traits that coexist within the same cell. We adapted an established phenomenological motility model that combines a reaction-diffusion system for the intracellular dynamics with a dynamic phase field to account for our experimental findings. KW - cell migration KW - amoeboid motility KW - keratocytle-like motility KW - modes of KW - migration KW - D. discoideum KW - actin dynamics Y1 - 2022 U6 - https://doi.org/10.3389/fcell.2022.898351 SN - 2296-634X VL - 10 PB - Frontiers Media CY - Lausanne ER -