Role of flexural stiffness of leukocyte microvilli in adhesion dynamics

Previous work reported that microvillus deformation has an important influence on dynamics of cell adhesion. However, the existing studies were limited to the extensional deformation of microvilli and did not consider the effects of their bending deformation on cell adhesion. This Rapid Communication investigates the effects of flexural stiffness of microvilli on the rolling process related to adhesion of leukocytes by using a lattice-Boltzmann lattice-spring method (LLM) combined with adhesive dynamics (AD) simulations. The simulation results reveal that the flexural stiffness of microvilli and their bending deformation have a profound effect on rolling velocity and adhesive forces. As the flexural stiffness of the microvilli decreases, their bending angles increase, resulting in an increase in the number of receptor-ligand bonds and adhesive bonding force and a decrease in the rolling velocity of leukocytes. The effects of flexural stiffness on deformation and adhesion represent crucial factors involved in cell adhesion.

Figure 1

(a) Schematic of the LSM for the microvilli. (b) Schematic of the simulation configuration.

Figure 2

The simulation results of the angular distribution of the microvilli at three different levels of the flexural stiffness.

Figure 3

The snapshots of the simulations at two levels of the flexural stiffness of (a) $K=0.1K_{\exp }$ and (b) $K=10K_{\exp }$. The green and red points represent microvilli tips and the places where the receptor-ligand bonds are formed.

Figure 4

The simulation results of the total local coordinate-based bond forces and their parallel and perpendicular components at three different levels of the flexural stiffness.

Figure 5

The simulation results of four different physical properties at different levels of the flexural stiffness. (a) Ratio ${\lambda }_{mv}$, (b) Average translational velocity, (c) Number of bonds, and (d) Deformation index $(L/H)$.