Incorporating pushing in exclusion-process models of cell migration

Area of Science:

• Cellular dynamics
• Biophysics
• Mathematical biology

Background:

• Individual cell migration is well-understood.
• Cellular interactions in crowded environments are increasingly studied.
• Existing models often use volume-exclusion but neglect active cell displacement.

Purpose of the Study:

• To model cell movement in crowded environments where cells actively displace neighbors ('pushing').
• To derive continuum partial differential equations from individual-level simulations.
• To analyze the impact of pushing on population-level diffusion.

Main Methods:

• Developed on- and off-lattice volume-exclusion position-jump models.
• Incorporated explicit 'pushing' behavior for cell displacement.
• Derived continuum partial differential equations for average domain occupancy.
• Compared simulation results with population-level models.

Main Results:

• Limited pushing shows good agreement between individual-level simulations and population-level models.
• Pushing increases the diffusion coefficient in the on-lattice model.
• Pushing decreases the diffusion coefficient in the investigated off-lattice model.

Conclusions:

• Active cell displacement ('pushing') significantly affects population-level dynamics.
• The impact of pushing on diffusion depends on the lattice type (on- vs. off-lattice).
• Careful selection of individual-level models is crucial for accurately representing cell-cell interactions.