Collective motion of cells: from experiments to models

Abstract

Swarming or collective motion of living entities is one of the most common and spectacular manifestations of living systems that have been extensively studied in recent years. A number of general principles have been established. The interactions at the level of cells are quite different from those among individual animals, therefore the study of collective motion of cells is likely to reveal some specific important features which we plan to overview in this paper. In addition to presenting the most appealing results from the quickly growing related literature we also deliver a critical discussion of the emerging picture and summarize our present understanding of collective motion at the cellular level. Collective motion of cells plays an essential role in a number of experimental and real-life situations. In most cases the coordinated motion is a helpful aspect of the given phenomenon and results in making a related process more efficient (e.g., embryogenesis or wound healing), while in the case of tumor cell invasion it appears to speed up the progression of the disease. In these mechanisms cells both have to be motile and adhere to one another, the adherence feature being the most specific to this sort of collective behavior. One of the central aims of this review is to present the related experimental observations and treat them in light of a few basic computational models so as to make an interpretation of the phenomena at a quantitative level as well.

Discontinuous fluidization transition in time-correlated assemblies of actively deforming particles

“…Such tissues display a surprisingly fast and collective dynamics, which would not take place under equilibrium conditions [10]. This dynamics has been ascribed to at least three distinct active processes [13]: (i) self-propulsion through cell motility such as crawling [15], (ii) self-deformation through protrusion and contraction [16][17][18], and (iii) cell division and apoptosis [14].…”

“…In contrast to externally driven systems (such as sheared materials), active matter is driven out of equilibrium at the scale of its microscopic constituents. Well-studied examples include biological tissues [3], bacterial suspensions [4] and active granular and colloidal particles [5][6][7][8].Epithelial tissues constitute a biologically relevant active system composed of densely packed eukaryotic cells [3,[9][10][11][12][13][14]. Such tissues display a surprisingly fast and collective dynamics, which would not take place under equilibrium conditions [10].…”

“…Epithelial tissues constitute a biologically relevant active system composed of densely packed eukaryotic cells [3,[9][10][11][12][13][14]. Such tissues display a surprisingly fast and collective dynamics, which would not take place under equilibrium conditions [10].…”

A hybrid model of cell migration in zebrafish embryogenesis

“…On the chemical scale we adopt diffusion and chemotaxis equations, while on the cellular scale typical effects of collective dynamics will be taken into account [1]. Although the cell are discrete points, we recover their shape through suitable detection radii.…”

“…Some species, especially those that can be easily treated experimentally, represent a paradigm for understanding more complex organisms, including humans. For this, in recent year collective dynamics has been extensively studied in a great variety of cell systems [1]. In [2], starting from the results obtained in recent biological experiments [3][4][5], we have have proposed a hybrid mathematical model describing self-organizing cell migration in the morphogenesis of the posterior lateral line system (PLL) in the model organism of zebrafish (Danio rerio).…”