Raja Paul and Ulrich S. Schwarz

Pattern formation and force generation by cell ensembles in a filamentous matrix

Proceedings of the IUTAM Symposium on Cellular, Molecular and Tissue Mechanics,
editors K. Garikipati and E.M. Arruda, in press, Springer 2009

Adhesion-dependent soft tissue cells both create and sense tension in
the extracellular matrix. Therefore cells can actively interact
through the mechanics of the surrounding matrix.  An intracellular
positive feedback loop upregulates cellular contractility in stiff or
tensed environments. Here we theoretically address the resulting
pattern formation and force generation for the case of a filamentous
matrix, which we model as a two-dimensional cable network. Cells are
modeled as anisotropic contraction dipoles which move in favor of
tensed directions in the matrix. Our Monte Carlo simulations suggest
that at small densities, cells align in strings, while at high
densities, they form interconnected meshworks.  Cellular activation
both by biochemical factors and by tension leads to a hyperbolic
increase in tissue tension. We also discuss the effect of cell density
on tissue tension and shape.