Influence of microenvironment on cell adhesion, polarization, and migration

Correspondence: Ivana Pajic-Lijakovic Faculty of Technology and Metallurgy, University of Belgrade, 11000 Belgrade, Serbia Email [email protected] We read an interesting article by Torres-Costa et al recently published in the International Journal of Nanomedicine. The influence of the rheological behavior of extracellular matrix (ECM) to cell adhesion and migration represents an important issue for various biomedical applications. The nature of cell adhesion and migration are stochastic as reported by Stokes et al. Cell migration should be considered in subcellular and cellular levels by applying fluctuation-dissipation theorem in the form of Langevin-type force-balance equations, and supercellular level by formulating mesoscopic mass and stress-balance equations. Torres-Costa et al experimentally and theoretically considered cell adhesion and migration as well as cell polarization on silicon surfaces. They developed the model and simulation by including only two basic criteria: (1) the tendency of cells to balance their adherence to the ECM; and (2) the tendency of cells to avoid overlapping with other cells. The authors introduce the concept of “adherence vector modulus.” However, the stability of adhesion complexes could not be described only by the adherence vector modulus. For the zero state of the adherence vector modulus, the stability of the adhesion complex must be dependent on conformational changes of ligand-receptor bonds. The changes depend on the ECM surface structure. Small conformational changes of ligand-receptor bonds also influence binding affinity. Bruinsma formulated the model for consideration of the adhesion complex stability at the subcellular level. He developed stochastic Langevin-type force-balance equations for describing the dynamics of adhesion complex changes. He considered using a viscous drug on the adhesion site, the spring force of bonds, and thermal random noise force. The influence of the rheological behavior of ECM on adhesion complex dynamics is quantified by rheological parameters: viscosity and Young’s modulus of elasticity. Bruinsma described potential and traction forces to explain the influence of conformational changes of adhesion complex on state of actin filaments. Consequently, the stability of adhesion complex should be correlated with structural cytoskeleton changes. Torres-Costa et al experimentally observed structural cytoskeleton changes through the distribution of actin fibers around the nuclei. The distribution of actin fibers is related to the strain energy density of the cytoskeleton and has a feedback action on the adhesion complex. The dynamics of adhesion complex should be correlated with cell polarization on one side and with cell migration on the other. Cell polarization caused by cell interactions with ECM has been described by the force dipoles or the Dovepress