Studies of Bending Effects of Microvilli of Leukocyte on Rolling Adhesion

It has been widely acknowledged that further understanding about the cell adhesion (e.g., leukocyte rolling adhesion) can help us gain more knowledge about the causes of relevant diseases and design more effective treatments and diagnoses. Although recent simulation studies considered the deformability of the leukocytes, most of them, however, did not consider the bending deformation of microvilli. In this paper, an advanced leukocyte model based on an immersed boundary lattice-Boltzmann lattice-spring model (LLM) and an adhesive dynamics (AD) is presented in details. The flexural stiffness of microvilli is introduced into the model for simulations of leukocyte rolling adhesion. This innovative model is applied to investigate the influences of bending deformation of microvilli on the process of leukocyte rolling adhesion and the underlying mechanism at different shear rates. It is demonstrated that the bending deformation of microvilli can be influenced by the flexural stiffness of microvilli and shear rates, resulting in the different rolling velocity of leukocytes, number of receptor-ligand bonds, and bond forces. The findings clearly indicate that the bending of microvilli plays a crucial role in the dynamics of leukocyte adhesion.